The golden ratio was studied peripherally over the next millennium. Abu Kamil (c. 850-930) employed it in his geometric calculations of pentagons and decagons; his writings influenced that of Fibonacci (Leonardo of Pisa) (c. 1170-1250), who used the ratio in related geometry problems, though never connected it to the series of numbers named after him The Golden Ratio er et begrep som brukes for å beskrive hvordan elementer i et kunstverk kan plasseres i den mest estetisk tiltalende måte. Men det er ikke bare et begrep, er det en faktisk forhold, og det kan bli funnet i mange kunstverk Det gyldne snitt (riksmål) eller det gylne snitt (bokmål og riksmål) vil si deling av en linje eller en flate i to deler slik at den minste delen forholder seg til den største som denne til hele linjen eller flaten.. Uttrykt som φ (phi) tilsvarer dette et irrasjonalt tall med verdi = + = , Man kan finne dette delingsforholdet igjen mange steder i naturen og spesielt på menneskekroppen Hvorfor trenger vi Golden Ratio? Vi trenger å reflektere visuelt tiltalende vår visjon, kultur og kunnskap på alle områder av livet vårt med et perfekt øye. Så vi kan gi den visuelle integriteten ved å bruke det gyldne forholdet vi har hatt siden universets dannelse i vårt daglige liv
Golden Ratio, Phi, 1.618, and Fibonacci in Math, Nature, Art, Design, Beauty and the Face. One source with over 100 articles and latest findings Golden ratio - Golden ratio. fra Wikipedia, den frie encyklopedi. Denne artikkelen handler om tallet. For The Ace of Base-album, se The Golden Ratio (album) . It is not evident that Fibonacci made any connection between this ratio and the sequence of numbers that he found in the rabbit problem (Euclid)
The principle of the Golden Ratio has been used in art and architecture for 2,500 years to create aesthetic and harmonious proportions, and many handbooks on graphic design recommend it . The value of the golden ratio, which is the limit of the ratio of consecutive Fibonacci numbers, has a value of approximately 1.618
Golden Ratio Calculator: Calculate the shorter side, longer side, and combined length of the two sides to figure out the Golden Ratio. goldenRATIO : Created for designers and developers, this app gives you an easy way to design websites, interfaces, layouts, and more according to the Golden Ratio This website by and for graphic designer Tim Roussilhe looks quite content-dense but is very well organized according to the Golden Ratio and Golden Spiral, which focuses on the text in the upper left section of the website. Your eye begins in the top-center with Bonjour My Name is Tim. It then travels past the description of what Tim does, on to the menu buttons, hits the logo in the. The Golden Ratio DKL. Søk på dette nettstedet. Welcome to our project on the Golden Ratio. Malta. Norway. Biographies. Fibonacci. Oppdraget. Our school and class. Phi-måleinstrument. Photos. Nettkart. Norway > Oppdraget. Hvordan har idéen om det gylne snitt påvirket menneskene og verden rundt oss fra de tidligste tider og fram til. The Golden Ratio, also called Divyank Ratio, is the most economical algorithm of Nature with which the perfect and most beautiful objects of the universe and Nature are designed The Fibonacci Sequence The Fibonacci sequence is possibly the most simple recurrence relation occurring in nature. It is 0,1,1,2,3,5,8,13,21,34,55,89, 144... each number equals the sum of the two numbers before it, and the difference of the two numbers succeeding it. It is an infinite sequence which goes on forever as it develops. The Golden Ratio/Divine Ratio or Golden Mean The quotient of.
Golden Ratio is a simple and convenient tool for calculating multiples and reciprocals of φ as decimal and integral sequences. The mathematical constant φ is a geometric proportion commonly found in nature. It has guided artists and architects over the centuries in their pursuit of aesthetic perfection Hvor er det dejligt med al den fine respons vi har fået på The Golden Ratio. Jeg har hele tiden godt selv kunne lide musikken, men havde ikke lige luret at så mange ville synes om den. Det giver rigtig god gejst. Vi snakker pt. om at få stablet en stribe koncerter på benene, do This video provides a basic explanation of the Golden Ratio and the Fibonacci sequence in an easy, enthusiastic, and accessible manner. Examples illustrate h.. Uttaleguide: Lær hvordan Golden Ratio uttales på Engelsk med innfødt uttale. Golden Ratio Engelsk oversettelse
The Golden Ratio is a mathematical ratio discovered and commonly found in nature, which is now visible almost everywhere like in architecture, music, paintings, modern design etc. When used effectively, it creates designs that are naturally and aesthetically appealing to the eye by way of their composition The Golden Ratio. The concept of the Golden Ratio is thousands of years old. It forms the foundation for many classic works of art and architecture, from the Great Pyramid of Giza in Egypt to artist Georges Seurat's Parade de cirque, and you'll often find it cited in encyclopedias and academic papers The golden ratio is the calculation of a short side, long side, and a combined length of two sides. If it seems confusing, then you will be pleased to know the golden ratio calculator can easily find the answers for you. You can learn more about the golden ratio below. What is the Golden Ratio? The golden ratio, which people also call the golden proportion or golden section, is the calculation. The Golden Ratio may be more complex, but as a photographer's skills evolve, so too does their understanding of space in their images. The Golden Ratio's mathematical equates to perfect balance - an essential tool in the photographer's arsenal Some photographers prefer the golden ratio over the rule of thirds, claiming that the rule of thirds is essentially the golden ratio simplified. But I'm a fan of the rule of thirds, because it's a) easier to remember in the field, and b) able to produce more spacious compositions, whereas the golden ratio tends to cluster key elements more tightly toward the middle of the frame
The golden ratio is typically denoted with the Greek letter, phi (φ), and has been studied by mathematicians throughout history, including Euclid (~300 BC). In definition, two values exhibit the golden ratio if the ratio of the sum of the two values to that of the larger quantity is the same as the ratio of the two quantities Vi vil gjerne vise deg en beskrivelse her, men området du ser på lar oss ikke gjøre det
The Golden Ratio is an irrational number, and thus an infinite number. It is not possible to compute its decimal expansion in a finite amount of time. 8 Comments. Show Hide 5 older comments The Golden Ratio has been defined using various names in the past as well as the present.Phi, the Golden Mean, the Divine Section, the Golden Proportion, and the Divine Proportion are a few to name. almost all the elements of nature consist of this magical ratio (1:1.618) Golden ratio 1. The golden ratio also/ golden proportion/ golden mean/ golden section/ golden number/ divine proportion is that a line is divided such that the ratio of the longer part of the line to the whole is exactly the same ratio as the shorter part of the line is to the longer part
golden ratio definition: 1. a mathematical ratio (= a relationship between numbers) of approximately 1.6, which is often. Learn more Golden Ratio App - For $2.99 on the Mac App Store, you can have this simple but effective app that lets you easily create golden ratio layouts. (Update: No longer available) Golden Ratio Typography App - Ensure that your typography is proportionate by creating columns of body text that follow the golden ratio The golden ratio is also apparent in the organisation of the sections in the music of Debussy's Image, Reflections in Water, in which the sequence of keys is marked out by the intervals 34, 21, 13 and 8, and the main climax sits at the phi position.. Golden ratio definition is - a ratio of two numbers in which the ratio of the sum to the larger number is the same as the ratio of the larger number to the smaller : golden section
Forhold (ratio), også kalt målestokkforhold og skala, er forholdet av en avbildet ting, avstand, område, osv. og virkelighet. Størrelsesforhold brukes ofte i modellbygging, arkitektur og kartlegging. Et forhold (ratio) angir hvor mange enheter på jordens overflate som er lik en enhet på kartet. Det kan uttrykkes som 1/100.000 eller 1:100.000 The Golden Ratio and The Fibonacci Numbers. The Golden Ratio is an irrational number with several curious properties.It can be defined as that number which is equal to its own reciprocal plus one: = 1/ + 1.Multiplying both sides of this same equation by the Golden Ratio we derive the interesting property that the square of the Golden Ratio is equal to the simple number itself plus one: 2 = + 1 The golden ratio combines a little bit of math, a little bit of nature, and a lot of practical application for designers. Let's take a look at what the golden ratio means for design, and a few tips for using it in your design projects. The golden ratio has been used throughout history to create design elements that have an ideal visual appeal It's bullshit. The golden ratio's aesthetic bona fides are an urban legend, a myth, a design unicorn. Many designers don't use it, and if they do, they vastly discount its importance What is this Golden ratio?It is the Phi Constant- 1.618.Phi is a superior design number of mathematics. The Creator has always used the very same number in numerous events in the universe; in our heart pulses, in the aspect ratio of DNA spiral, in the special design of the universe called dodecehadron, in the leaf array rules of plants called phylotaxy, in the snow flake crystals, in the.
Nov 1, 2014 - Golden Ratio in Photos, Golden Spiral in Photos,Photo Composition,Golden Ratio in Photography. See more ideas about Golden ratio, Photo composition, Golden spiral The golden ratio and Fibonacci sequence appears in the petal count of flowers. Most flowers have petals that are either two, three, five, or more petals which are all part of the divine sequence. For example, lilies have 3 petals, buttercups have 5, the chicory flower has 21, and the daisy has 34 The study is to emphasis the importance of 'Golden Ratio',an impeccable mathematical tool which exist in nature.The research work gradually shifts from the mathematical explanation of golden ratio to its application in designs.The aspect The golden ratio is an irrational number equal to .It is one of the two solutions of the quadratic equation: It has the special property of being one more than its reciprocal. Equivalently, two positive real numbers are in the golden ratio if the ratio of to is the same as the ratio of to. The golden ratio has many mysterious reappearances in geometry and number theory The Golden Ratio does indeed help improve designs and visual content, but you don't need to fully master it to make use of it. Many editing apps will have already incorporated the Golden Ratio in their templates and presets, so you won't need to understand it at all in order to actually use it
Golden ratio in nature An incredible discovery is when we find a spiral in a human body. Your ear is in the golden ratio, your face is also. The relationship between the bones is 1: 1.61. The Golden ratio is obvious when we look at the seagull.. Definition of golden ratio What is Golden Ratio? I'll try to explain the easiest way golden ratio définition, signification, ce qu'est golden ratio: 1. a mathematical ratio (= a relationship between numbers) of approximately 1.6, which is often. En savoir plus The Golden Ratio. and the human body This exercise is divided into 3 parts: A. The golden ratio. Measure the following: Distance from the ground to your belly button. Distance from your belly button to the top of your head. Distance from the ground to your knees. Distances A, B and C. Length of your hand. Distance from your wrist to your elbo The golden ratio, also called the golden number, divine proportion, etc., has a very close association with the Fibonacci sequence. It is often represented by the Greek letter phi, φ \varphi φ or ϕ \phi ϕ. For the sake of uniformity, we shall denote the golden ratio by ϕ \phi ϕ. We say two quantities a a a and b b b, where a > b a>b a > b.
Two quantities are in golden ratio to one another if their ratio is the same as the ratio of their sum to the larger of the two quantities.. Criticism [edit | edit source]. Psychologists, starting with Gustav Fechner (1876), have proposed that humans could somehow recognize this ratio in all kinds of proportions and experience it as the most aesthetic proportion The golden ratio is a famous geometry idea with a connection to ancient Greece. (When it came to mathematics, physics, astronomy, philosophy, drama, and the like, those ancient Greeks sure did kick some serious butt.) The figure below shows the Parthenon on the Acropolis in Athens. Built in the fifth century B.C., it is an [
The Golden Ratio and antiquity Since ancient days the golden ratio in the form of the golden rectangle has been used extensively. The Greek sculptor Phidias, (ca. 490-430 BC), made extensive use of the golden ratio in his works. The structures of the Roman classical era are said to be designed within the Golden Ratio Golden Ratio is an S-Tier skin for the Painter, Edgar Valden. It is obtainable from Season 13 Essence 1, and will grant the player the character Painter along with it. 1 Appearance 1.1 Physical 1.2 Outfit 1.3 Item 1.4 Effects 2 Trivia 3 Gallery 4 Links Edgar now has light blonde hair, still fashioned into a low ponytail with strands framing his face and bangs. He still has pale peachy skin and. The golden ratio is present throughout the world in design, the human body, nature, photography, art, and more. It seems to be nature's favorite equation. Actually, when you start looking for it, you might have a hard time un-seeing it. Here are some examples: Art. The golden ratio has been used for centuries and is no stranger to High. The Golden Ratio is a mathematical ratio that's commonly found in nature. It can be used to create visually-pleasing, organic-looking compositions in your design projects or artwork. Whether you're a graphic designer, illustrator or digital artist, the Golden Ratio, also known as the Golden Mean, The Golden Section, or the Greek letter phi, can be used to bring harmony and structure to your.
The golden ratio is the ratio of approximately 1 to 1.618. These are extremely important numbers to mathematicians. But what do they mean to us artists? Well there have been studies which suggest designs set out using the golden ratio are aethetically pleasing. We can use the golden ratio to help design our paintings and position our subjects Golden ratio tattoo at first may seem just as a simple spiral, but it has a very profound meaning. But of course, despite the mathematical and geometrical background, it is a beautiful tattoo. No matter how we put it - body art is all about visuals The golden ratio, also known as φ (phi) or approximately 1.618, is a number with some trippy properties. It's no wonder that many people treat the golden ratio with a great deal of mysticism, because (here's the cliche part) it appears repeatedly in nature and also crops up in many fields of mathematics Golden ratio observed in human skulls / Johns Hopkins University, October 3, 2019. In a new study investigating whether skull shape follows the Golden Ratio (1.618 ), Johns Hopkins researchers compared 100 human skulls to 70 skulls from six other animals, and found that the human skull dimensions followed the Golden Ratio T he Golden Ratio is number that shows u p all over the human body, from the length of the arms and legs compared to the torso, and it seems to define what proportions look best;.
The Golden Ratio is present in the Sydney Opera House. But more than this, the golden ratio has been used for the façade of great buildings - from the Parthenon to the Great Mosque of Kairouan, and all the way through to modern landmarks such as the Sydney Opera House and the National Gallery in London The Golden Ratio . We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads Based on the Fibonacci Sequence, the Golden Ratio describes the relationship between two proportions. Fibonacci numbers, like many elements found in nature, follow a 1:1.61 ratio - this is what we refer to as the Golden Ratio, and as it forms such a common sight in nature, it feels pleasing to the eye when we use this same ratio in our design work The Golden Ratio is most commonly represented as the Golden Rectangle, a rectangle with side-length ratio of 1.618:1. Golden Rectangles also have the property that if you cut off a square, you. The golden ratio in the human body. Many artists and designers use the golden ratio in their works because it is perceived as more pleasing to see. In the century. 25 B.C. the Roman architect Marcus Vitruvius Pollio remarked on a similarity between the human body and a perfect building
The Golden Ratio is a mathematical ratio of 1.618:1, and the number 1.618 is called Phi. Golden Ratio of Beauty Phi measures the symmetry of a face to determine one's beauty. Source: Twitter. In this measurement, the length and width of a person are measured, and then the length is divided by width. According to the Golden ratio for a. The golden ratio states that if A/B is equal to B/C then those two numbers are in the golden ratio. The golden ratio gives birth to the golden spiral. It is a logarithmic spiral which is found all over the place in nature but with a growth factor that's equal to the golden ratio. Meaning that for every quarter turn the spiral makes, the. The golden ratio can also be applied to other geometric forms, including triangles, prisms, pyramids, circles, polygons, and more. Some mathematicians have found that the human face follows the golden ratio. The more closely the proportions of the human face adhere to the golden ratio, the more attractive it is Relation to Golden Ratio. The relation of Fibonacci terms with the Golden Ratio is already discussed in this post. In brief, the n th term of the Fibonacci sequence is given by Binet's Formula, where. is the Golden Ratio, and. Finding the n th Fibonacci term. Since. for all n ≥ 0, the number F n is the closest integer t The importance of the Golden Ratio has been somewhat exaggerated over the years in the popular media. The scientific evidence for many of these examples of this ratio and the Fibonacci series is doubtful at best. When we look at phyllotaxy or the.
I am looking for Golden Ratio formulas. Google searches only provide width from known height or height from known width. Instead, what I want to calculate is: width from known area height from known are Les mer på Platekompaniet.n
golden ratio noun the ratio of two lengths, equal in value to (1 + √5)/2, and given by b / a = (b + a)/ b; it is the reciprocal of the golden section and also equal to (1 + golden section)Symbol: Φ Compare golden sectio The golden ratio is usually taken as the ratio between lines of different lengths and also the ratio of the sum of the lengths of both these lines to the length of the long line among them. This ratio is the ideal ratio for designs and has been used at multiple places by a number of designers and architects HOW TO CALCULATE YOUR OWN GOLDEN RATIO. You can calculate you own Golden Ratio. Measure the circumference of your upper body at the point at which your bust is most prominent (B), your waist at its narrowest (W), and your hips at the widest (H), you can do it in cm or inches it doesn't matter.Then measure from your bust line down to your waist (label this distance BW), and measure from your.
Media in categorie Golden ratio Deze categorie bevat de volgende 128 bestanden, van in totaal 128. 01 Goldener Schnitt-J. Wentzel Kaschuben-1717.svg 422 × 364; 185 k Below you may find the answer for: Golden ratio symbol crossword clue.This clue was last seen on Wall Street Journal Crossword October 24 2020 Answers In case the clue doesn't fit or there's something wrong please let us know and we will get back to you. If you are looking for older Wall Street Journal Crossword Puzzle Answers then we highly recommend you to visit our archive page where. The golden ratio has occasionally been used in the design of architecture, sculpture, and fine art for centuries. I recently redesigned our logo, and in this post I will cover the history of the mathematical golden ratio, and show how I used its guiding principles when implementing our golden ratio logo design to make it more distinct and quickly recognizable The golden ratio is a mathematical ratio used to create balance and beauty in a picture. You can find it in nature, paintings, architecture, and the human face. Phi, the 21st letter of the Greek alphabe t, symbolizes (φ) the golden ratio. History has shown that using the golden ratio can enhance beauty. Sen et al. (2008) believed that Leonardo. Define golden ratio. golden ratio synonyms, golden ratio pronunciation, golden ratio translation, English dictionary definition of golden ratio. n. See golden section. American Heritage® Dictionary of the English Language, Fifth Edition


- Are you from the Eastern Cape?
- Have you passed your matric with more than a 60% average?
- Did you get more than 60% for Mathematics (not Mathematical Literacy)
- Do you want to study for a Mathematics, Science and Technology related undergraduate qualification?
- Are you already accepted in a South African university of your own choice for 2022?
Click the link below to download the application form.
Please note: CLOSING DATE – 28th February 2022


The paired comparisons test dialog is shown below. Here, you enter the information that Maritz Stats needs to compute the results of a paired comparisons test.
Show me how to use it! To see an example of how to use the paired comparisons test, click here.
Show me how it works! For more information on the formula used for the paired comparisons test, click here.
The Base is the total number of respondents, including No Preference and No Answer. If you enter percentages, this number will be used to calculate the raw number of respondents in each category.
For each of the two groups you are comparing, you can enter either percentages or raw number who fell into that group. Selecting either Percent Selecting or Number Selecting enables the appropriate controls to enter this information.
When conducting a paired comparisons test, you can make one of two assumptions. Either those respondents who indicate no preference can be ignored, or you can assume that this percentage/number will be evenly split between the two categories. If you choose to split these responses, enable this check box, and then enter either the number or percent of respondents who fell into this category.
If you are interested in detecting significant differences in one direction (for example, preference for A is GREATER THAN preference for B), then select a one-tailed test. If you are interested in detecting significant differences in either direction, then select a two-tailed test.
The confidence level indicates the degree of confidence that the interval actually encompasses the unknown population parameter variable. For most applications, the default of 95% should be used. However, you have the option of being more stringent (using the 99% confidence level) or less stringent (90% or 80% confidence level) based on your needs. The higher the confidence level, the less likely it is that differences will be found significant.
The results are presented in three stages. First, the z-value is presented. This can be used to compare to a z-table if a significance level other than 80%, 90%, 95%, or 99% is desired. Second, the critical value for this test is presented based on the significance level selected. Finally, a simple "yes" or "no" indicates if these two groups are significantly different based on the information provided.


Stagnation Point Flow over a Stretching/Shrinking Sheet in a Carbon Nanotubes with Suction/Injection Effects
Keywords:stagnation point flow, stretching/shrinking sheet, carbon nanotubes, suction/injection effects, dual solutions
This research is to explore the stagnation point flow problem in carbon nanotubes (CNTs) with suction/injection impacts over a stretching/shrinking sheet. Nonlinear ordinary differential equations systems are transformed from the governing partial differential equations by applying similarity transformation, thus resolved numerically using a bvp4c solver in MATLAB. Two types of CNTs are used which are SWCNTs (singlewalled) and MWCNTs (multi-walled) and water as the base fluids. Influence of the velocity, temperature, skin friction and Nusselt numbers are studied and displayed in the graphs form. It is concluded that the suction effect could widen the range of solutions exist and the effect of injection acted on the contrary. Also, the solutions are dual for shrinking sheet while unique for stretching sheet.


The Libra machine learning toolkit includes implementations of a variety of algorithms for learning and inference with Bayesian networks (BNs), Markov networks (MNs), dependency networks (DNs), and arithmetic circuits (ACs). Libra stands for Learning and Inference in Bayesian networks, Random fields, and Arithmetic circuits.
Libra is the first open source machine learning toolkit to directly support BNs with decision tree conditional probability distributions (CPDs), dependency networks, Markov networks with sparse factors, or arithmetic circuits. (The WinMine Toolkit and Ace were partial inspirations for Libra and offer some overlapping functionality, but neither is open source.) Libra's strength is exploiting local structure such as context-specific independence and feature-based representations to allow richer structure, more compact models, and more efficient inference.
Libra is released under a modified BSD license.
An even more up-to-date development version can be obtained from the source code repository:
Version 0.5.0 introduces Markov network weight learning, converting dependency networks to Markov networks (DN2MN), iterated conditional modes, and more. See the changelog for details.
All methods are implemented in OCaml, in order to obtain the best possible speed while keeping the code compact and easy to work with. To compile the source code, you must have a UNIX-like environment (Linux, OS X, Cygwin) with a recent version of OCaml installed.
For more information, see the documents below:


However, we know there might be an omitted variable bias because we do not observe ability. . A multiple regression model enables us to estimate the effect on Y i Y i of changing a regressor X1i X 1 i if the remaining regressors X2i,X3i,Xki X 2 i, X 3 i , X k i do not vary. elevation, slope) changes by more than 10% in linear regression, the variable you added can be considered . Omitted variable bias occurs when a relevant explanatory variable is not included in a regression model, which can cause the coefficient of one or more explanatory variables in the model to be biased. Some other factor may determine both the nature of the political . One phenomenon to keep in mind when analyzing survey data is self-serving bias. Two outcomes are possible: either there is no bias or there is a positive bias or negative bias on the partial effects of other explanatory variables in the restricted model. 37 Full PDFs related to this paper. This has positive bias because the poverty rate is correlated with the rate of female-headed However, the positive relationship may be driven by self-selection into education; i.e. general, omitted variables bias (also known as selection bias) is the most serious econometric concern that arises in the estimation of treatment effects. proper random sampling. Omitted variable bias arises when the variance of the conditional distribution of . Discussing omitted variable bias in VSP e.g. Omitted variable bias happens when two things are true at the same time.
This biased approach to predictive analytics. Another famous explanation is given by the distinguished financier Kenneth French, who suggested firms delay bad news for the weekends, . Full PDF Package Download Full PDF Package. Let me introduce the second issue by considering a slight extension of the above frame- 18th Edition. . That is, due to us not including a key variable Download Download PDF.
Ommitted variable bias is the bias that arises in the OLS estimators when a relevant variable is omitted from the regression. [Unfortunately, just as in our calculation of omitted variables bias from Section 3.3, the conclusions do not carry over to more general models. But they do serve as a useful guide.] Direction of Omitted Variable Bias. O A. When calculated from a sample, R 2 is a biased estimator.
True positive rates decrease substantially for mixed data compared to the baseline. EXAMPLES 2.1 Omitted Variable Bias Example: Once again, will be biased if we exclude (omit) a variable (z) that is correlated with both the explanatory variable of interest (x) and the outcome variable (y).The second page of Handout #7b provides a practical demonstration of what can BUY. The Value of Advertising . In this paper we examine the potential for omitted variable bias in WTP for quality changes. Causality and potential outcomes You cannot test for omitted variable bias except by including potential omitted variables unless one or more . Solutions - Additional Study Questions for Omitted Variable Bias. Controlling for unmeasured characteristics with causal models in neighbourhood environment studies is important because omitted variables (e.g. A positive omitted variable bias means that a positive covariance of the omitted variable with both a regressor and the dependent variable will lead the OLS estimate of the included regressor's coefficient to be greater .
Selection Bias: Draft Lottery Omitted variable bias can cause a misleading analysis of the data and a distortion of the study's actual . In a fixed-effects model, subjects serve as their own controls. The variable I is termed the "dependent" or "endogenous" vari-able; E is termed the "independent," "explanatory," or "exogenous" variable; is the "constant term" and the "coeYcient" of the vari-able E. EEP/IAS 118 Spring '15 Omitted Variable Bias versus Multicollinearity S. Buck 2 2. Using school district data like that used in this chapter, she regresses district average test scores on the number of computers per student. The positive cross-country relationship between income and democracy in the 1990s is depicted in Figure 1, which shows the association between the Freedom House measure . the bias is positive; if both are of opposite signs, the bias is negative. That is, suppose we are trying to fit the model Y = 0 + 1 X 1 + however, there is another variable X 2 that is correlated with X 1 and influences Y, then the estimate for 1, which we can call 1 ^, will be biased. Provide an example to explain how panel data can be used to eliminate certain kinds of omitted variable bias One example of panel data is the wage regression. For example, findings from observational studies suggest a positive association between density of . An omitted variable is often left out of a regression model for one of two reasons: 1. IThe Table Corr(omitted variable,x) positive negative Corr(omitted variable,y) positive upward bias downward bias negative downward bias upward bias.
Should make sense intuitively. selection bias & reconstruction spending (CERP, JPE 2011) -3 0 3 6 e-100 -50 0 50 100 CERP coef = .015, (robust) se = .004, t = 3.9 . . Publisher: McGraw Hill. do not solve the omitted variable bias of OLS estimates . Defining Omitted Variables Bias Omitted variables bias (or sometimes omitted variable bias) is a standard expression for the bias that appears in an estimate of a parameter if the regression run does not have the appropriate form and data for other parameters. If this set excludes 0, the results from the controlled regression can be considered robust to omitted variable bias. If this assumption does not hold then we can't expect our estimate ^ 1 to be close to the true value 1. In terms of DAGs, there is a backdoor path from education to wage passing through ability that is not blocked and therefore biases our estimate. The idea/hope is that whatever effects the omitted variables have on the subject at one time, they will also have the same effect at a later time; hence their effects will be constant, or "fixed." HOWEVER, in order for this to be true, the omitted . Conversely, if the correlation between an explanatory variable and an unobserved relevant variable is negative, omitted variables bias will occur in a downward direction." This result surprised me at first. Omitted variable bias: violation of consistency From the omitted variable bias formula b 1!p 1 + 2 Cov (X i;W i) Var (X i) we can infer the direction of the bias of b 1 that persists in large samples Suppose W i has a positive effect on Y i, then 2 >0 Suppose X i and W i are positively correlated, then Cov (i; i) >0 This implies that b of bias called omitted variable bias. Self-Serving Bias. . This relationship is highly robust across samples, variable Murphy's Law: the other line is going much faster. This has positive bias because the poverty rate is correlated with the rate of female-headed rogeneity in estimating the effect of variables that are not changing over time. Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018.
The advantage of 2SLS is that it is at least consistent, where OLS is not, in the case of omitted variables.
come, hypothesized to be positive; and = the "noise" term reXecting other factors that inXuence earn-ings. Thus, the effect of Ads in the limited model (8.9) also captures some of the positive effect of ratings. 16.2 Simultaneity bias in OLS We have shown how omitted vars lead to biased coefficients. This problem occurs because your linear regression model is specified incorrectlyeither because the confounding variables are unknown or because the data do not exist. Professionals may do this when initially conducting the study by forgetting to monitor a certain variable or when analyzing and presenting the data of their study. A. IV vs. The omitted variables problem is one of regression analysis' most serious problems. Identification is achieved by structuring the cross-equation resi dual covariances via a set of common omitted variables, which are in turn related to a set of measured exogenous variables. If both of those are true, then omitting the variable makes . expand_less. In political economy, instrumental variables often exploit "quasinatural experiments". The omitted variable bias is a well-documented problem in house price modelling . Usually, this means accidentally working with a specific subset of your audience instead of the whole, rendering your . This is called the "exclusion restriction". In short, the omitted variable bias emerges if an omitted third variable causes the independent and dependent variable. . Bias only occurs when the omitted. But if we omit female headed households from the model we obtain a much higher estimate of the effect of poverty on homicide (.475). estimates store omitted. While this intuition is correct for small alpha, it is wrong once alpha is sufficiently large. The higher percentage of discretized variables, \(p . More information about STATA can be found at the company Web site. . Will b 1 be an unbiased estimator of the . So you check which one is the shortest and queue up there. The OLS estimators of the coefficients in multiple regression will have omitted variable bias a) if an omitted determinant of Yi is correlated with at least one of the regressors b) only if an omitted determinant of Yi is a continuous variable . We also think ratings should have a positive effect on sales. If b 2 =0 or Cov(,)0XX 12 = , there is no omitted variable bias. Omitted Variable Bias. However, due to high correlation between Sydney and Parramatta distance variables, the latter was excluded. unmeasured preferences) may bias relationships between environmental variables and health outcomes . Omitted variable bias (OVB) is one of the most common and vexing problems in ordinary least squares regression. You are finished with shopping and you want to pay. (Stock & Watson, Review the Concepts, Exercise 6.1) A researcher is interested in the e ect on test scores of computer usage. In the example above, our unobserved U impacts negatively the outcome but its positively correlated with the treatment, which will result in a negative bias. Write out the STRUCTURAL MODELS (equation derived from economic theory--model in terms of causal effects): (1) y 1 = 1 y 2 + 1 z 1 + u 1 zs are exogenous variables (2) y 2 . This result, however, may be difficult to interpret or perhaps indicative of self-selection bias as the recorded positive effect on the likelihood of self-employment is noted in 2006 when no MOB has been established. In this case, the omitted variable bias occurs. 2. individuals who have the most to gain from more education are more likely to stay. An omitted variable bias occurs when researchers don't consider an important variable when recording and sharing their results. To assess the size of the bias consider the OLS-estimator for b = cov(x;ye ) var(ex) = cov(x+u; x+ ) var(x+u) 1 The R-squared value in your regression output has a tendency to be too high.
But if we omit female headed households from the model we obtain a much higher estimate of the effect of poverty on homicide (.475). This correlation determines positive omitted variable bias in the estimates. If b 2 <Cov(,)0XX 12, the omitted variable bias is negative. First, the omitted variable must explain part of the decision to hire clerks, the outcome. An optimistic attitude causes an upward bias by using optimistic assumptions in building a model which may be, for example, the economy is expected to grow in the next period at a healthy rate, a competitor is unlikely to respond to our . 2000. Now let's look at how simultaneity leads to a bias. Everyday example of Omitted Variable Bias: Imagine a grocery store. 6.1 Omitted Variable Bias; 6.2 The Multiple Regression Model; 6.3 Measures of Fit in Multiple Regression; 6.4 OLS Assumptions in Multiple . This information allows prediction of omitted variable bias in the unestimated omitted variable coefficients. Fig. - Hard to sign the bias. 1 Omitted Variable Bias: Part I Remember that a key assumption needed to get an unbiased estimate of 1 in the simple linear regression is that E[ujx] = 0. 3. If the direction of correlation between omitted variable \(z\) and \(x\) is the same as that between \(x\) and \(y\), we will observe upward bias in our estimate of \(b_1\), and vice versa if the correlations go in opposite directions. Based on . Omitted Variable Bias As detailed above, omitting a variable from a regression model can bias the slope estimates for the variables that are included in the model. An independent researcher is interested in finding out whether there exists a positive relationship between the number of years of formal education received by an individual and the number of years of formal education received by each of his parents. More specifically, OVB is the bias that appears in the estimates of parameters in a regression analysis, when the assumed specification is incorrect in that it omits an . . A short summary of this paper. This paper represent an attempt to address these issues through the col-lection of a novel dataset that combines survey and administrative informa-tion. Statistical bias is a systematic tendency which causes differences between . omitted variable bias. The bias results in the model attributing the effect of the missing variables to those that were included. Rerunning the analysis and including area as an independent variable solves this mystery. The principal finding is a substantial downward bias in regres Course Number: 14.33. Read Paper. Omitted-variable bias is the bias that appears in estimates of parameters in regression . For example, in online businesses, business managers check the behavior of the user to make decisions for upcoming product projects. While it may not be possible to identify all omitted variables, a good research model explores all variables that might impact the dependent variable. The link between omitted variables bias, causality, and treatment effects can be seen most clearly using the potential-outcomes framework. 1 Omitted Variable Bias Exercise 1.1. This is a problem referred to as omitted variable bias. Answer: 1 - Upward or downward bias is caused by the optimistic or pessimistic attitude of a forecaster. In statistics, omitted-variable bias (OVB) occurs when a statistical model leaves out one or more relevant variables. Omitted Variable Bias. We call this problem omitted variable bias. of omitted variable bias (OVB) in a general multivariate setting - a longstanding issue in econometrics; the second issue relates to the possibility of reducing bias of OLS estimators . Omitted Variable Bias, example 2 Thus, the "true" effect of poverty on homicide is .136. 4. This bias occurs when professionals only consider the participants who have had a positive outcome from the product or action under study. equation thus creating an endogeneity bias. If the omitted-variable has zero partial effects in the unrestricted model or zero correlation/covariance (independence between explanatory variables) there is no bias incurred on other partial effects in the . We extend the theory of McConnell  and analyze the effects of changes in own-price and cross-prices on WTP for quality changes. In a linear regression model, the reason we control for variables is to prevent the omitted variable bias (OVB). I previously had the following intuition: An omitted variable is only a problem if it affects both y and x.Thus the omitted variable bias probably becomes worse if the confounder z affects y or x more strongly. Returning to the example of children's screen time from above helps to clarify this. . Table 2 shows that, even in the baseline model, true positive rates are much lower than true negative rates, hence the estimated models are likely to have omitted variables bias rather than redundant variables. with the dependent variable of interest indirectly: the instrumental variable works exclusively through the independent variable to affect the dependent variable. . Therefore, the asymptotic bias (or inconsistency) in the OLS estimator of "1 has the same sign as "2/(1 % "2" 1). Guidelines for Writing an Empirical Paper ( PDF) A tutorial on the statistical software program STATA ( PDF ), with associated data file [dataforrecitation.dta ( DTA )]. If the correlation between education and unobserved ability is positive, omitted variables bias will occur in an upward direction. Omitted Variable Tests The data set nlsy.dta contains information on 252 women in work in the United States A regression of the log of hourly pay on years of work experience (exper), years at the current firm (tenure) and years of education (educ) gives the following .
There are 3 lines and you want to pick the one where you have to spend the least time. If this bias affects your model, it is a severe condition because you can't trust your results. Robert J Franzese. Similarly, the selection bias from unobservable factors should be over about 7 times higher than selection on observable variables when TFP_LP is dependent variable. ISBN: 9780079039897. If we just stop there, the effect from the feature would be biased (a.k.a, Omitted Variable Bias) because an important Confounding variable, AGE, is not included in the model. quietly regress y x1. Study Guide on the Omitted Variables Bias ( PDF) Instructor: Prof. Michael Greenstone. If the correlation between education and unobserved ability is positive, omitted variables bias will occur in an . If the correlation between education and unobserved ability is positive, omitted . In WWII there was apparently positive selection into the military. This strong positive correlation is a result of the close proximity between Parramatta and Sydney CBD within the Sydney metro area. Partial effects of Omitted Variable and Correlation with Other Explanatory Variables. No Bias Scenario. than the other way round. Data for the variable is simply not available. unobservability of variables or unavailability of data force them to omit such variables from regression models. Controlling for the incidence of informal employment appears to be key for removing a positive omitted- variable bias in the estimate of the partial correlation between unemployment and the digital economy, which is due to the existence of a negative bivariate correlation between unemployment and informality on the one hand, and a negative . selection bias. motivation, that are also likely to have a positive e ect on performance. Second, the omitted variable must also be correlated with grades, the explanation. Survivorship bias can change the validity of a study because it overlooks important data points. Using R, I conducted a set of simulations to illustrate this general pattern of omitted variable biases summarized in Table 2.
Omitted Variable Bias, example 2 Thus, the "true" effect of poverty on homicide is .136. If you increase spending on Ads, the original ratings won't change . Omitted variable bias; Cause-effect bias; Funding bias; Cognitive bias; Statistical bias #1: Selection bias. is usually positive d) is the difference in means in Y between the two categories. We extend the theory of McConnell  and analyze the effects of changes in own-price and cross-prices on WTP for quality changes. Author: Carter. . This means that if OLS has a negative/positive bias, 2SLS will also have it. Omitted variable bias is a type of selection bias that occurs in regression analysis when we don't include the right controls.-----. In this paper we examine the potential for omitted variable bias in WTP for quality changes. Since ex and u are positively corre-lated (from (2)) we can see that OLS estimation will lead to a negative bias in b if the true is positive and a positive bias if is negative.
- Famous Food In Chicago Illinoisbarrett Elementary School
- Polycarbonate Solvent
- When One Person Changes In A Relationship
- Guns N Roses Welcome To The Jungle Discogs
- Genius Challenge Chemical Reactions Answer Key
- Linear System Calculator
- 1994 Mazda Miata For Sale Near Illinois
- Most Romantic Beach Destinations In Europe


A few weeks ago I got this idea in my head that it would be fun to make a pillow in a cube shape. I love Amy Butler’s Gumdrop Pillows, but I wanted something different, something a little smaller, that would be affordable to stuff!
So I sat down with pencil and paper and drew a whole bunch of diagrams and did the math…and then I did the math again when I realized I had made an error in calculating seam allowances, and then I did the math again to create a cutting layout that would work on a 1 metre piece of fabric. (I bought the fabric before I had even started drawing the design…not wise, I know, but I was at the fabric store and it was there, and 1 metre seemed like a lot at the time…..) Glad to put all of those high school math classes into practice…ok, you’re right, I didn’t have to build any matrices to create this pattern….glad to put all of those elementary school math skills into practice! Perhaps this year I should teach my class how to sew – that might take care of our math class for the year! 🙂
It’s square, it’s soft, it’s squishy, perfect for sitting or for propping up your feet. I kind of like sewing things I’ve designed myself. Especially when it works out the way I want it too! I might have to do more of that in the future.


Theory and Parameterization of Infections and Waves by Covid-19: A 6-Countries Data Analysis
MetadataShow full item record
Institute of Electrical and Electronics Engineers
2021 IEEE 21st International Conference on Bioinformatics and Bioengineering (BIBE)
From data of USA, Japan, Germany, UK, Italy and Russian, it is claimed that the Global pandemic dictated by the dynamics of Corona virus exhibits distributions that would correspond to a morphology of Bessel-like type. Under the assumption that the pandemic contains phases of infection denoted by the velocity and acceleration of propagation of virus, then a model of polynomials given by the integer-order Bessel functions is proposed. These polynomials enter in a statistical approach to define the law of infections as function of time for the ongoing global pandemic. From this, the data evolution and their different behaviors are interpreted in terms of the different phases including the Delta variant for the recent months until August 2021.
- Ingeniería de Sistemas


Give your third grader the third grade multiplication resources they need to succeed in future math lessons. Learning third grade multiplication is made easy with worksheets that give students visual clues, activities that allow your class to learn together, and games that make learning fun! Students in need of additional third grade multiplication help should see our second grade.
Browse 3rd grade georgia pacing guide resources on Teachers Pay Teachers, a marketplace trusted by millions of teachers for original educational resources.
This packet was designed to practice the 3rd grade Georgia standards. It started as a review for the kids when they started 4th grade when they return from summer vacation. This way I could see how much of a refresher we need on 3rd grade standards before teaching 4th grade standards. But this packet also makes a great review for the end of the 3rd grade year prior to the Georgia Milestones.
The McDuffie County School System is committed to academic excellence with a focus on rigor, relevance and relationships.
Set students up for success in 3rd grade and beyond! Explore the entire 3rd grade math curriculum: multiplication, division, fractions, and more. Try it free!
Welcome to our resource site for parents and students for 3rd Grade Math. As of this year, our Gum Springs will be using Eureka Math (used in EngageNY) as our foundation resource for math instruction. Our 3rd-grade team has created this site to help support our students and parents in navigating through the standards, expectations, and demands for Math. What is Eureka Math? Eureka Math is a.
Homework Contact Me Here are a few websites you may wish to visit: Buckland Elementary Gates County Schools Homework Help and Interactive Math Games: Georgia Public Schools Parent Live Binder Third Grade Math Practice Support for Grade 3 Math Families FunBrain (Check out the math section!).
Georgia Habitat Regions Unit Test Study Guide. Habitat Jeopardy. Powered by Create your own unique website with customizable templates. Get Started.


In my previous blog post we considered the general weighted moving average. In this post we aim to give an overview of some specific types of moving averages. Specifically, we cover “ordinary” moving averages and mention some examples of exotic moving averages.
Ordinary Moving Averages
These are the most common types of moving averages used to time the market.(1)
Simple Moving Average
The Simple Moving Average (SMA) computes the arithmetic mean of n prices
SMA_t(n) = frac1n sum_i=0^n-1 P_t-i.
In this moving average, each price observation has the same weight wi=1 (ψi = 1/n). The average lag time and smoothness of SMA are given by
textLag time(SMA_n) = fracn-12, quad textSmoothness(SMA_n)=n.
Obviously, increasing the size of the averaging window increases both the smoothness and the average lag time of SMA.


Investment Calculator: What It Is and How to Use
Investment calculator is that type of tool which allows you to calculate various options for return on investment, taking into account the reinvestment. It can be used both to check the investment portfolio and to draw up a financial or investment plan.
An investor calculator is an excellent tool for calculating the required amount of capital for a comfortable retirement, but it can also be used for any other financial purposes. It is a good financial helper with the help of which you can understand is it worth to invest money. Sometimes ideas come when you don’t wait for it. So, if you can’t support your ideas financially, turn to any lending company, but take care. Calculate if it is profitable for you.
What Is Reinvestment?
It is also called compound interest. It is a kind of income accrual income. Albert Einstein called the compound percent formula “the greatest mathematical discovery of modernity.” But it is so elementary! Look at the schedule where we have compared simple interest and compound interest.
How to Use the Investor Calculator
You should just fill in the data required for calculating income in the financial online investor calculator.
- Initial deposit – the amount of money that was invested at the beginning;
- Expected return – deposit interest for 1 period (month, quarter, year);
- The term of the investment (the number of periods) during which it is planned to keep funds on the account, taking into account the monthly replenishments or withdrawals;
- Account replenishment – a period of time (once a month, 2 months, quarter, 4 months, half a year, year) through which you will add funds to the main deposit;
- Amount of replenishment – the amount of funds that you are willing to add to your account.
Having all the data mentioned above you can start choosing a suitable calculator. Sy the way, we have collected 7 the most popular investment calculators.


If you get excited about numbers, today is a spetacular day.
It is a rare opportunity to present the date in binary form (that’s not the actual binary date however).
So just how rare is it?
Have you figured out how many times in a century you can represent the date with 1s and 0s without getting your arse kicked in public?
Very Happy New Year to you and yours! if you’re in Dallas, I have extra Cotton Bowl tickets, give a shout.
01/01/00, 01/10/00, 10/01/00, 10/10/00
01/01/01, 01/10/01, 10/01/01, 10/10/01
01/01/10, 01/10/10, 10/01/10, 10/10/10
Percentage of days you can be slightly cool with numbers, or feel slightly, smuggly numerically superior – also known as “clever” . . .
Or, .03% of the century.
We only have 3 more left this century, so grab your binary buddies and part hats. We’re gonna party like it’s 10-10-10!


Risk is well defined in the world of finance, usually as the probability of a loss event or historical volatility. Probability is the likelihood of the event. Volatility has the aspect of an amount of loss. The problem is, one cannot consider just the one or the other. Instead ISO 31000, a standard for risk management, as used in IT security or project management defines risk as
where likelihood is the probability of the loss and impact is the size of the loss. One could now make a complicated quantitative risk model based on this, but a rough set of categories should be enough for private investors.
So we define impact and likelihood each with 4 levels with example:
|1||critical||leveraged losses larger than 100%|
|2||severe||Total loss of capital|
|3||medium||Temporary losses during a crash|
And likelihood also with 4 levels and example:
|2||very likely||Seasonal variations|
|3||likely||Trends, bull vs. bear markets|
So when looking a certain investment vehicle one can roughly calculate the risk factor as likelihood number multiplied with impact number, which results in a risk factor between 1 and 16.
The nice effect is that one can build a risk acceptance matrix where one can with color mark those risk factors that one can carry (green) and those that one does not want to accept (red).
So suppose, everything up until 4 is super, until 9 is acceptable for you and everything above that is a no-go. Now when you determine the risk of a investment instrument, you can determine for yourself, wether to use this investment or not. Of course the judgement of impact and likelihood is not completely objective but rather a bit subjective. But in the end better than having no risk model at all and better simple than too complicated, just good enough.
Now one should not only look at risk, as banks and insurances do. Where there is risk there should also be a chance. Unfortunately in this direction this is not automatically true, whereas one can always say that every chance has a risk but not vice versa. In the one direction from chance to risk there is a nearly causal relation in the other one not.
So we can extend our risk model by a chance model like so:
where we make a simple categorization of opportunity with our 4 levels and examples as such:
|4||huge||tenbagger, leveraged wins|
And of course we can extend our risk matrix to a risk/chance matrix
Marking in this matrix again the acceptable risk and the acceptable chance is helpful to determine not only what risk should be avoided but also what chance is the minimum one wants to reach.
There is though a problem, of course one would like to have a high chance with a low risk, but this does not exist. But what exists, is a high risk with a low chance, that’s call bad business. The normal case is that with a high chance comes a high risk and with a low risk comes a low chance, unfortunately. So the investor needs to look for an investment that has both an acceptable chance but also an acceptable risk, so usually somewhere in the middle.
The good thing is though, that when there is risk, there is usually a way to mitigate this risk and where is a chance there is a way to foster this chance.
What’s important is that an investor uses a risk- and chance-based mental model and the systematic model presented here should serve as a simple, yet powerful such way of thinking to analyse a investment upfront.
For example see the video and hope that this proves to be useful.


Came across this in my applied math grad course. The correct answer is incredibly simple, the equation of a circle. But in order to arrive at that solution a fair bit of geometry, algebra, and solution of a non-linear ODE is required.
A curve passing through (1,2) has the property that the length of a line drawn between the origin and intersecting perpendicular with the normal extending from any point along the curve is always numerically equal to the ordinate of that point on the curve. Find the equation of the curve.
Put another way: “Any curvature has a normal and a tangent. Draw the normal out and draw a line passing from the origin that is perpendicular to that (this line will be parallel to the tangent). The length of this line is equal to the ‘y’ of the point from which the normal emanates.”
Here’s a crude diagram:
Solution strategy is as follows:
We have some function y=f(x). We pick any point on f, and call that point (x,y) and draw a normal to the function at that point. We then draw a line from the origin such that it intersects with the normal perpendicularly at a point (a,b). The length of the vector (a,b) is equal to the ordinate of the point on the function from which the normal emanates, ‘y’. So that |(a,b)| = y.
What function satisfies this condition, and also passes through the point (1,2)?
Here’s the completed solution: BLAM!


Senior defense is coming up, and it’s given me the opportunity to look back at all the projects I’ve done over the years at CCNTH. In this post, I’m going to be writing about my Easter Island game, which you can play in your browser at https://nathanlackie.net/easterisland/ (press f to turn on flashlight). I am using this game as my Junior year artifact in my senior defense. It’s fairly unassuming on the surface, but a lot of work went into this game.
One thing I focused on when making this game was procedurally generated terrain. Which, in simpler terms, basically means the shape of the island land wasn’t manually designed by me, but instead is generated by mathematical functions. If you picture an island in your head, you can imagine the shape it would take. How would you model an island with a math function? Well, you can’t use a typical 2D graph like a circle or parabola, you need to use a 3D graph. Imagine a plane, with an X-direction moving left and right, and a Y-direction moving up and down:
You can imagine this being a top-down view of the island. Each point on this plane has an associated X and Y value. We can then make a third axis to this plane perpendicular two both of our existing axis. This looks something like this:
The X and Y inputs represent the position on the island, and the new Z-axis represents the height of the land.
Okay, now that I’ve done my best at explaining a 3D graph, we still need a function that generates the rough shape of an island given these X and Y coordinates. Back to what I said earlier, picture an island in your head. One of the key features of an island is that it’s higher above sea level the closer you get to the center. So we want our function to return higher values the closer we are to the origin of our X/Y plane. To do this, I used the distance formula, which is simply sqrt(x^2+y^2). There’s a problem though, this returns the distance from the origin, so this is precisely the opposite of what I want to achieve, with further values from the center being larger. Luckily, the solution to this is fairly simple, I can just take 1 minus the distance. After smoothing out this distance function using something called smoothstep, we get a 3D graph looking like this:
(made in my Desmos 3D grapher, which is a whole other topic)
As you can see, this takes the very general shape of an island. In real life though, things aren’t perfectly smooth like the 3D graph above. Real terrain has bumps. I used a method called perlin noise, which, to be fully honest, I don’t really understand the functions behind how it’s generated. Luckily for me, Unity has a built-in method for generating Perlin Noise. An example of perlin noise is shown below:
This is a representation of perlin noise, plotted on the X/Y plane mentioned earlier. Black spots are a Z value of zero, white spots are a Z value of one, and gray spots are somewhere in-between. By adding this noise to my height graph, it adds some randomness to the terrain, so it’s not perfectly smooth. This ends up looking something like this:
As you can see, I had a lot of fun with this project. As I near the end of this blog post, I’m realizing I didn’t write much about Senior defense or any of the other components of the game, but instead just nerded out about terrain generation algorithms. I plan on going into Computer Science as a career, so I chose this project as a senior defense artifact due to how many Computer Science concepts I used in making it. This is the longest blog post I’ve written so far by far, so I hope you found nearly 700 words about video game math interesting.


来源：百度文库 编辑：北方网 时间：2020/01/26 10:38:55
From Wikipedia, the free encyclopediaJump to: navigation, search It has been suggested that this article or section be merged with Cross tabulation . (Discuss)
In statistics, contingency tables are used to record and analyse the relationship between two or more variables, most usually categorical variables.
Suppose that we have two variables, sex (male or female) and handedness (right- or left-handed). We observe the values of both variables in a random sample of 100 people. Then a contingency table can be used to express the relationship between these two variables, as follows:
The figures in the right-hand column and the bottom row are called marginal totals and the figure in the bottom right-hand corner is the grand total.
The table allows us to see at a glance that the proportion of men who are right-handed is about the same as the proportion of women who are right-handed. However the two proportions are not identical, and the statistical significance of the difference between them can be tested with a Pearson's chi-square test, a G-test or Fisher's exact test, provided the entries in the table represent a random sample from the population contemplated in the null hypothesis. If the proportions of individuals in the different columns varies between rows (and, therefore, vice versa) we say that the table shows contingency between the two variables. If there is no contingency, we say that the two variables are independent.
The example above is for the simplest kind of contingency table, in which each variable has only two levels; this is called a 2 x 2 contingency table. In principle, any number of rows and columns may be used. There may also be more than two variables, but higher order contingency tables are hard to represent on paper. The relationship between ordinal variables, or between ordinal and categorical variables, may also be represented in contingency tables, though this is less often done since the distributions of ordinal variables can be summarised efficiently by the median.
The degree of association between the two variables can be assessed by a number of coefficients: the simplest is the phi coefficient defined by
where χ2 is derived from the Pearson test, and N is the grand total number of observations. φ varies from 0 (corresponding to no association between the variables) to 1 (complete association). This coefficient can only be used for 2 x 2 tables. Alternatives include the tetrachoric correlation coefficient (also only useful for 2 x 2 tables), the contingency coefficient C and Cramér's V. C suffers from the disadvantage that it does not reach a maximum of 1 with complete association in asymmetrical tables (those where the numbers of row and columns are not equal). The tetrachoric correlation coefficient the Pearson product-moment correlation coefficient between hypothetical row and column variables with Normal distributions, that would reproduce the observed contingency table if they were divided into two categories in the appropriate proportions. It should not be confused with the Pearson product-moment correlation coefficient computed by assigning values 0 and 1 to the cells. In tables with more than two levels for each variable an analogous quantity is called the polychoric correlation coefficient.
The formulae for the other coefficients are:
k being the number of rows or the number of columns, whichever is less.
C can be adjusted so it reaches a maximum of 1 when there is complete association in a table of any number of rows and columns by dividing it by .
The term contingency table was first used by Karl Pearson in "On the Theory of Contingency and its Relation to Association and Normal Correlation" in Drapers' Company Research Memoirs (1904) Biometric Series I.


Red River Charter Academy’s (RRCA) curriculum is based on science, technology, engineering, art and math (STEAM) disciplines that integrate all academic content into a cohesive investigative approach to teaching and learning.
A high-quality STEAM education prepares students for high-demand jobs and contributes to the vitality of their families, communities, and local economies. Our STEAM curriculum is rigorous and allows each of our students to become problem solvers, innovators, inventors, self-reliant, logical thinkers, and technologically literate. In addition to the STEAM curriculum, we emphasize to our students through our fine arts courses that in order for STEAM to be complete, “A” (art) must be added, changing it to STEAM – science, technology, engineering, art, and math; a strong indication of RRCA’s belief that arts nurture creativity and problem-solving abilities.
READY TO GET STARTED?
RRCA will be serving grades 6-12 for the upcoming 2023-2024 school year.
Red River Charter Academy promotes high achievement in all subjects through a demanding curriculum, extensive support services, and the use of data-driven, best practice teaching methods. Let’s get started.
©2023 Red River Charter Academy.


The 14th of March is written as 14.3 in the UK, but as 3.14 in America, because of this, National Pi Day is celebrated around the world on this day. Pi (Greek letter “π”) is the symbol used in mathematics to represent a constant — the ratio of the circumference of a circle to its diameter — which is approximately 3.14159.
The Maths and English Department at North Shropshire College (NSC) decided it would be a great opportunity to celebrate the day with staff and students throughout the College. The day consisted of a number of entertaining games and tasks which had Maths and English embedded into them, showing the students that Maths has functional uses and is not just a subject and exam to be passed at the end of the year.
Wayne Young, Maths Lecturer at NSC commented, ‘It has been a math-e-magical day for both students and staff who enjoyed the overall experience. The students now have a deeper understanding of Pi and where it comes from and even had fun along the way’.
A number of the Maths and English staff were live on BBC Radio Shropshire in the morning after they changed the lyrics to the song ‘House of the Rising Sun’ and learnt the guitar and ukulele to perform on the breakfast show.
Jo Millington, Head of English and Maths at the College who organised the day added, ‘As Maths and English is incorporated into all areas of the curriculum at NSC, we wanted to embrace these skills promoting English and Maths in an engaging way’.
For more information about courses at NSC, or to apply, visit the website at www.nsc.ac.uk or you can call the Admissions Team on 01691 688080.
Pictured – Staff before they performed live on BBC radio Shropshire. L-R – Kim Dobson, Maxine Bellingham, Wayne Young, Jo Millington, Kev Machin and Paul Wilson.


When teaching mathematics to students with mild to moderate disabilities,
When teaching mathematics to students with mild to moderate disabilities, special education teachers first will identify student challenges. Identifying these challenges is vital in addressing the specific needs to help students continue to flourish in their academics. There can be numerous areas in which students struggle in mathematics and identifying differentiation strategies to help lessen these struggles is vastly important.
Allocate at least 3 hours in the field to support this field experience.
With your mentor teacher, identify a student or small group of students with disabilities who would benefit from differentiation and engagement strategies during an upcoming math lesson or activity.
Part 1: Student Challenges
With the mentor teacher, observe the student or small group of students while they work on math problems in class. Identify areas where the student or students seem to struggle.
Areas of concern where students may struggle include (but are not limited to):
· Output difficulties
· Organizational difficulties
· Language difficulties
· Attention difficulties
· Visual spatial or ordering difficulties
· Difficulties with multiple tasks
After observing and noting concerns, discuss with the student/students whether the areas you identified were challenging for them. Continue to work with them with guided practice and support.
Discuss your findings with your mentor teacher. Offer intervention strategies you could implement to help the students learn the math concepts being taught. With your mentor teacher, decide on 1-2 strategies to further develop in Clinical Field Experience C and implement in Clinical Field Experience D.
Part 2: Reflection
After observing and talking with the students and your mentor, summarize and reflect upon your experiences in 250-500 words, including:
· Your initial conversation with the mentor teacher, identifying how the student or students were chosen.
· Areas where the students seem to struggle.
· Summarize the conversation between you and the students discussing the areas that seemed to challenge them. Were they in agreement with you, or did they feel that they did not struggle or did not need support? If so, how did you continue to support them?
· Strategies you suggested to the mentor teacher, his or her feedback, and what strategies the two of you ultimately decided you would implement (which may be the same or different from what you originally suggested).
· Explain how you will use your findings to further assist the students while working with them in this placement. This will also help prepare you for Clinical Field Experiences C and D, as well as your own future classroom engagements.
Description of the Assessment
Special education teachers will first identify student challenges when teaching mathematics to students with mild to moderate disabilities. Identifying these challenges is critical in addressing the specific needs that will allow students to continue to thrive academically. There can be numerous areas in mathematics where students struggle, and identifying differentiation strategies to help alleviate these struggles is critical.
Set aside at least three hours in the field to support this field experience.
Identify a student or small group of students with disabilities who would benefit from differentiation and engagement strategies during an upcoming math lesson or activity with your mentor teacher.
Part 1: Student Difficulties
With the mentor teacher, observe the student or small group of students while they work on math


The What Is Discrete Math Diaries
Mathematics has an indispensable function in answering all these questions. You ought to have strong algebra skills to work in calculus. Math is a substantial part of computer science.
The branch of mathematics that addresses discrete variables is referred to as discrete math. The homework is actually important, and you need to work hard at it. c++ programming homework It is very important, and you need to work hard at it.
What Is Discrete Math Secrets That No One Else Knows About
Regardless, it’s a computer. Nobody equation is the most likely likely to model the comprehensive thing. It is probable that you will select a red marble.
There was a lovely approach to help with that issue, however. With any large estate, there are lots of decisions to make and time passes quickly. There was an attractive system to help with that problem, however.
The very first thing which you ought to do is to try to locate facts which are about the problem available. The very first thing that you ought to do is to attempt to discover facts that are about the problem available. By definition, something straightforward to solve is straightforward to check, because all you’ll want to do is resolve the problem to attempt it.
It’s also often true that if you truly understand the issue, you can observe a solution. http://gpadmissions.osu.edu/apply/grad.html More than only the answer, you need to understand how to do the issue. There’s another issue too.
The Ultimate Strategy to What Is Discrete Math
Nonetheless, in the future, it’s guaranteed to make fruitful outcomes. It was not always called engineering. It is tough to think that how not looking at data can help you!
The choice of statistical test is in part contingent on the plan of Here, http://alldrugs24h.com/, http://allpills24h.com/, http://buycialisonline24h.com/, http://buypills24h.com/, http://buypillsonline24h.com/, http://buysildenafilonline24h.com/, http://buytadalafilonline24h.com/, http://buyviagraonline24h.com/, http://cheapviagraonline.com/, http://help-essay.info/, http://orderviagracheap.com/, http://tadalafilsildenafil.com/, here, here, here, here, here, here, here, here, here, here, here. the analysis and the type of information collected. You might locate the data here. What can be accomplished by data science.
Up in Arms About What Is Discrete Math?
Broadly speaking, you need past a computer science degree to elevate your chances of landing an entry level computer computer software engineering job. Scheduling tutoring classes beforehand may also be an extremely good option. It’s challenging to be successful in technical courses.
The history of discrete mathematics has involved numerous challenging domyhomeworkforme difficulties that have focused attention within regions of the area. There’s a range of disciplines of mathematics. There are lots of reasons why the mathematics is necessary for machine learning.
Luckily, it’s relatively easy here so as to calculate everything directly. A set is an assortment of unique objects. An empty set comprises no elements.
Messy data and varying map resolutions mean that many of the methods to measure borders and compactness is readily manipulated. Late assignments won’t be accepted after the solutions are distributed. To understand the reason, you’ve got to learn about the notion of convexity in optimization.
Content MathML uses just a few attributes. The truth that many LaTeX compilers are comparatively forgiving with syntax errors exacerbates the matter. Differential equations cannot be utilized since they’d represent a system which’s continuous.
In the event the equation is more interesting, or when Here, http://alldrugs24h.com/, http://allpills24h.com/, http://buycialisonline24h.com/, http://buypills24h.com/, http://buypillsonline24h.com/, http://buysildenafilonline24h.com/, http://buytadalafilonline24h.com/, http://buyviagraonline24h.com/, http://cheapviagraonline.com/, http://help-essay.info/, http://orderviagracheap.com/, http://tadalafilsildenafil.com/, here, here, here, here, here, here, here, here, here, here, here. you need to refer to it later on, you may want to assign it a number using the equation atmosphere. Make certain that you choose the suitable side lengths for each rectangle. Otherwise it is called a disconnected graph.
What Is Discrete Math
Quite simply, it’s the value that is probably to be sampled. In order for the whole proposition to be true, both statements must be true. Generally speaking, a nontrivial equivalence relation has to be antisymmetric.
You can place a number on the sum of anger. Any number might be the next member. If it’s a positive number, you want to decrease 1.
You will need to spot the physicians assistant programs that supply the type of training you want. You should spot the physicians assistant programs that supply the kind of training you want. He may pick the questions freely.
There’s an extensive collection of possible approaches here. It gives you a substantial edge. To start with, pattern languages make an attempt to manage relationships explicitly.
Statisticians find employment in a large number of fields. Student mentors share some crucial qualities. Logic is the use of reasoning principles.
The Characteristics of What Is Discrete Math
Squares of numbers that aren’t prime numbers will have more than 3 factors. You should not presume that your mean is going to be one of your initial numbers. To locate the median, your numbers must be listed in numerical order from smallest to largest, which means you may need to rewrite your list before it’s possible to discover the median.
What Is So Fascinating About What Is Discrete Math?
There are a lot of resources out there to provide assist. Besides offering somewhere to conserve all your precious eBooks, the eBook reader software even provide you with a large number of features to get the ability to raise your eBook reading experience compared with the standard paper books. Math for a whole lot of people is a gigantic scary monster.


A fixed deposit (FD) is one of the simplest and hence one of the most popular forms of investment. Its popularity arises from the fact that it is a safe and secure investment with few of the risks associated with other investments such as stocks or real estate, and the fact that it gives higher returns as compared to regular deposits. Thus rather than having your money lying around in your savings account, it is always a better idea to invest it in a fixed deposit scheme where it can earn higher interest. The exact interest on a fixed deposit scheme varies from bank to bank. It also depends on the duration of your deposit – the longer the duration, the higher the interest rate is likely to be. Before you invest, however, is important to know what your returns are going to be. You do this either manually using a pen and paper or you can use an FD calculator such as this one provided by Finserv MARKETS.
How to Calculate Interest on Fixed Deposit Investment?
You can calculate the interest on your FD in two ways:
- Using Pen and Paper – When calculating the interest rate on FD yourself using pen and paper it is important to understand that there are two kinds of interest rates applicable to FDs:
Simple Interest – This is applicable to FDs with a tenure of up to 6 months. The formula for calculating simple interest is:
Interest = Principal x Rate of Interest x Tenure of FD/ 100
Compound Interest – This is usually applicable to FDs with a tenure longer than 6 months. Even in this case, there are two kinds of possibilities depending on the type of payout you want :
- Monthly Payout – You take your interest payments at the end of each month. The interest rate in this case is usually calculated at discounted rates.
- Payout at Maturity –You take your payout at the end of the term period of your FD.
In case you opt for the second option, you can utilize the power of compounding as compound interest is applicable in this case. The formula for calculating compound interest is slightly more complicated.
Maturity Amount = Principal (1+rate of interest/n) ^ (n * Tenure)
Where n = number of times the amount is compounded in a year.
- Using FD Interest Calculator – As you can see, calculating FD interest using pen and paper can get complicated. Therefore, it is more convenient to use an FD calculator that gives you more accurate results. You can use this simple FD rate calculator by Finserv MARKETS. All you need to enter in the calculator are the deposit amount, the tenure of the FD, and the interest rate. The FD calculator will do the rest. If you do not know the prevailing FD interest rate, you can check the best rates from Finserv MARKETS to enter in the FD interest calculator.
In a Nutshell
FDs are a safe and convenient vehicle for investing your savings. However, the rate of interest and the duration for which you are investing make a big difference. It is advisable to calculate the maturity amount you can expect at maturity beforehand. The most convenient way of doing this is using an online FD interest calculator that gives you fast and accurate results.


CAMBODIAN MATHEMATICIAN TO DELIVER VALEDICTORY ADDRESS AT 2015 COMMENCEMENTPosted by: Cambodian | Posted on: June 7, 2015
ខ្ញុំចប់ពីសាលា១០មករា៧៩ខេត្តសៀមរាបដែរ…កញ្ញាតោ គឹមសុី ជាជំនាន់ប្អូន…ខ្ញុំមានមោទនភាពចំពោះកញ្ញាខ្លាំងណាស់….សូមប្រសិទ្ធិពរអោយកញ្ញាបានជោគជ័យនូវរាល់បំណងស្វែងរកថ្នាក់បណ្ឌិតសិក្សា។
I also graduated form 10 January 1979 High School. I am proud of you Miss Kimsy Tor, wish you success in your graduate school effort. (from Sophoan Seng facebook)
CAMBODIAN MATHEMATICIAN TO DELIVER VALEDICTORY ADDRESS AT 2015 COMMENCEMENT
Kimsy Tor ’15 receives Donald J. Carty Valedictory Medal.
Cambodian-born Kimsy Tor, a member of Manhattan College’s class of 2015, moved to the U.S. at the age of 18 to begin her freshman year in Riverdale, N.Y. Four years later, Tor will address her fellow classmates and their families as the 2015 valedictorian at the College’s 173rdCommencement on Sunday, May 17.
Tor graduates with a B.S. in mathematics and a minor in computer science. In the fall, she will move to Paris to pursue a Master of Science in mathematics at the prestigious Pierre and Marie Curie University, which is part of The Sorbonne University alliance. She hopes to pursue her Ph.D. in Paris and eventually return to Cambodia to teach, where approximately 10 residents hold doctorate degrees in mathematics. Subsequently, education is important to the development of Cambodia with an adult literacy rate of only 74 percent and two in 10 Cambodians living below the poverty line. Tor plans to make a difference in Cambodian education.
As Tor’s mentor and major adviser, professor Helene Tyler, Ph.D., first met Kimsy at Cambodia’s Royal University of Phnom Penh (RUPP) while teaching an intensive winter math course. With Tyler’s encouragement, Tor applied to Manhattan College and was accepted. Tyler is an associate professor of mathematics at Manhattan College. “Kimsy Tor is one of the most broadly intelligent people I have ever known. Her intellectual curiosity is insatiable and she is remarkably adept at making connections across various subjects,” says Tyler. “Kimsy has participated in some of the most challenging and competitive summer programs available to undergraduate students.”
Tor also credits Manhattan College with teaching her the value of giving back to others. As a result, she has served the New York City community at Math Encounters at The Museum of Mathematics and Friends Without A Border. She participated in the College’s Lasallian Outreach Volunteer Experience (L.O.V.E.) in Arizona, and the E3MC – Engaging, Educating, Empowering Mean Change program at Rikers Island Correctional Facility in New York City. In her spare time, she has earned a brown belt in Tae Kwon Do and is a stained glass hobbyist.
Tyler also described how Tor helped to raise money to help Cambodian students who want to study mathematics after giving a speech at the Pi Mu Epsilon induction in 2014 on the obstacles Cambodian students face. The money provides scholarships to three students at RUPP.
As an avid researcher in mathematics and computer science, Tor has been published in several research journals. She has also presented her research at numerous conferences, including the 2015 Joint Mathematics Meetings, the largest mathematics meeting in the world, the Hudson River Undergraduate Mathematics Conference, the International Conference on Fibonacci numbers and Their Applications at Rochester Institute of Technology, the Spuyten Duyvil Undergraduate Mathematics Conference hosted by Manhattan College, and others in Canada and the U.S.
Tor finishes her undergraduate studies with a 3.91 GPA. She is trilingual in English, French and Khmer, and has been a member of the math honor society Pi Mu Epsilon since 2012, serving as the president since 2013. In addition, she has been a member of the Dean’s List since 2011, and a member of the following honor societies: Sigma Xi (national honor society to encourage research in the sciences), Epsilon Sigma Pi (College-wide honor society), and Phi Beta Kappa (dedicated to the idea of excellence in the liberal arts and sciences). She was a recipient of the Thomas O’Malley International Scholarship and the College’s Presidential Scholarship during her four years at Manhattan College.
“It is my great honor to be chosen to be a valedictorian,” Tor says. “It took a great amount of hard work of the whole Manhattan College community to get me here and I want to take this opportunity to thank them for everything they have done. I owe them a great debt of gratitude.”
Manhattan College will award approximately 750 undergraduates with degrees in some 40 major fields of study from its Schools of Arts, Business, Education and Health, Engineering and Science on May 17.
David J. O’Brien, Ph.D., professor emeritus of history and Catholic Studies at the College of the Holy Cross, will deliver the keynote address at the College’s Undergraduate Commencement. He will also receive an honorary Doctor of Humane Letters.
For complete information on Commencement 2015, visitmanhattan.edu/commencement.


Usage of Eulerian and Hamiltonian Graph in Pandemic Situation
Keywords:Graph, Eulerian, Hamiltonian, path, circuit, pandemic, hospital
The existence of Euler and Hamiltonian graph make it easier to solve real life problem. During the time of pandemic “Covid -19” it is very essential for each one of us to be vaccinated. Vaccination is done in the hospitals by using Eulerian and Hamiltonian graph not only prevent people from infecting but also increase the speed of vaccination. In this paper, authors have discussed the use of graph theory to effectively handle the covid – 19 pandemic situations in the allocation of patients to appropriate hospitals. The work done in this paper, may be utilized for the hospital – patient management as well as for the study by upcoming researchers to utilize the graph theory in any complicated situations.
V. Sutaria, “A Hamiltonian and Eulerian cycles”, International Journal of Mathematics Trend and Technology, vol. 3, iss. 5, pp. 208-212, 2016.
A. Kumar and SHUATS, “A study on Euler Graph and it’s applications,” Int. j. math. trends technol., vol. 43, no. 1, pp. 9–15, 2017.
H. Ahmed, “Graph routing problem using Euler’s theorem and its applications,” Engineering Mathematics, vol. 3, no. 1, p. 1, 2019.
H. Fleischner, “(Some of) the many uses of Eulerian graphs in graph theory (plus some applications),” Discrete Math., vol. 230, no. 1–3, pp. 23–43, 2001.
M. S. Rahman and M. Kaykobad, “On Hamiltonian cycles and Hamiltonian paths,” Inf. Process. Lett., vol. 94, no. 1, pp. 37–41, 2005.
F. Keshavarz-Kohjerdi and A. Bagheri, “Hamiltonian paths in some classes of grid graphs,” J. Appl. Math., vol. 2012, pp. 1–17, 2012.
Ł. Waligóra, “Application of Hamilton’s graph theory in new technologies,” World Scientific News, vol. 89, pp. 65–76, 2017.
S. A. L. T. Cherin Monish Femila, “Hamiltonian cycle and Hamiltonian path decomposition of fan graphs,” International Journal of Scientific Research in Mathematical and Statistical Sciences, vol. 6, no. 2, pp. 207–211.
W. Alhalabi, O. Kitanneh, A. Alharbi, Z. Balfakih, and A. Sarirete, “Efficient solution for finding Hamilton cycles in undirected graphs,” Springerplus, vol. 5, no. 1, p. 1192, 2016.
K. ChandraBora and B. Kalita, “Particular Type of Hamiltonian Graphs and their Properties,” Int. J. Comput. Appl., vol. 96, no. 3, pp. 31–36, 2014.
How to Cite
This work is licensed under a Creative Commons Attribution 4.0 International License.


Fifty two Houston area Harmony students have been asked to participate at this year’s Houston Pre-freshman Enrichment Program (PREP), a summer program. Houston PREP is hosted by the College of Sciences and Technology at the University of Houston – Downtown. For many years, they have been helping prepare Harmony students entering college in the areas of mathematics, science and engineering. Houston PREP focuses on helping students from economically and socially disadvantaged populations. The program kicks off with an engineering/ career day on July 12.


First, some utility functions. Given a list, the "breaks" function does a break at each possible place, and the "plucks" function uses that to shove each possible element to the front of the list in order.
import List breaks list = zip (inits list) (tails list) plucks = map (\(a,(b:bs)) -> (b:a++bs)) . filter (not.null.snd) . breaks
Once we have plucks, the recursive permutation generator is (almost) a one-liner:
lexPerm  = [] lexPerm list = concatMap (\(a:as) -> map (a:) $ lexPerm as) $ plucks list nthLexPermNaive list n = (lexPerm list) !! n
(With "nth" counting from 0, of course.) For purposes of the problem at hand, this is plenty fast enough: I'm supposed to solve the problem in a minute, and I can get the millionth permutation in 10 seconds on my Mac. But 10 seconds is on the order of 10 billion operations with today's computers, which makes that pretty cheesy in the absolute sense, so I took a walk to grab some coffee and thought about it.
Of course we don't have to create the Library of Babel; we just want to index it. (Literally) exponentially better is, rather than generating all the permutations before the one we want, counting our way down to it:
facs = scanl (*) 1 [1..] nthLexPerm  _ =  nthLexPerm list n = (a : nthLexPerm as r) where (q, r) = divMod n $ facs !! (length list - 1) (a:as) = (plucks list) !! (fromIntegral q)
That is, we divide the permutations into buckets according to which list element goes first, count the size of the buckets with the factorial function, and figure out which bucket n is in; that tells us which list element is first (or next), and then we do it again with the rest of the list.
Here any reasonable-sized problem is done in a quarter of a second, and we can find the 1776779232335715732683331380583415166995
(If we wanted to permute the whole text of Moby-Dick, this might run into trouble: in the process of figuring out the first letter, we have to spend at least quadratic time computing the factorial of the length of the remaining part of the list. For the earlier permutations, we could trim this down a bit by doing the factorial mod n.)
This entry was originally posted at http://adb.dreamwidth.org/1238.html. Please comment there using OpenID.


I joined the faculty of the Institute of Economics, Academia Sinica in 2018 as an assistant research fellow after receiving my PhD in Economics from UC Berkeley. My research interest is in Econometrics.
The maximum utility estimation proposed by Elliott and Lieli (2013) can be viewed as cost-sensitive binary classification; thus, its in-sample overfitting issue is similar to that of perceptron learning. A utility-maximizing prediction rule (UMPR) is constructed to alleviate the in-sample overfitting of the maximum utility estimation. We establish non-asymptotic upper bounds on the difference between the maximal expected utility and the generalized expected utility of the UMPR. Simulation results show that the UMPR with an appropriate data-dependent penalty achieves larger generalized expected utility than common estimators in the binary classification if the conditional probability of the binary outcome is misspecified.
This paper proposes a nonparametric estimator of the counterfactual copula of two outcome variables that would be affected by a policy intervention. The proposed estimator allows policymakers to conduct ex-ante evaluations by comparing the estimated counterfactual and actual copulas as well as their corresponding measures of association. Asymptotic properties of the counterfactual copula estimator are established under regularity conditions. These conditions are also used to validate the nonparametric bootstrap for inference on counterfactual quantities. Simulation results indicate that our estimation and inference procedures perform well in moderately sized samples. Applying the proposed method to studying the effects of college education on intergenerational income mobility under two counterfactual scenarios, we find that while providing some college education to all children is unlikely to promote mobility, offering a college degree to children from less educated families can significantly reduce income persistence across generations.
"Utility-Maximizing Binary Prediction via the Nearest Neighbor Method and Its Application to Credit Scoring"
We propose nonparametric k-nearest neighbor prediction rules under the framework of utility-maximizing binary prediction with possibly many predictors. One of these prediction rules, with an attempt to ‘break’ the curse of dimensionality, is constructed based on the predictors selected by variable selection methods. We establish that these prediction rules, allowing for the data-dependent selection of parameter k, are utility consistent under regularity assumptions. Such utility consistency is confirmed by the simulation results. We illustrate these prediction rules with an application to credit scoring in peer-to-peer lending and find that common predictors of the business cycle yield limited improvement in profitability.
The forecast combination puzzle is often found in literature: The equal-weight scheme tends to outperform sophisticated methods of combining individual forecasts. Exploiting this finding, we propose a hedge egalitarian committees algorithm (HECA), which can be implemented via mixed integer quadratic programming. Specifically, egalitarian committees are formed by the ridge regression with shrinkage toward equal weights; subsequently, the forecasts provided by these committees are averaged by the hedge algorithm. We establish the no-regret property of HECA. Using data collected from the ECB Survey of Professional Forecasters, we find the superiority of HECA relative to the equal-weight scheme during the COVID-19 recession.
We propose a counterfactual Kaplan-Meier estimator that incorporates exogenous covariates and unobserved heterogeneity of unrestricted dimensionality in duration models with random censoring. Under some regularity conditions, we establish the joint weak convergence of the proposed counterfactual estimator and the unconditional Kaplan-Meier (1958) estimator. Applying the functional delta method, we make inference on the cumulative hazard policy effect, that is, the change of duration dependence in response to a counterfactual policy. We also evaluate the finite sample performance of the proposed counterfactual estimation method in a Monte Carlo study.
"Testing Monotonicity in a Model with Nonseparable Time-Invariant Heterogeneity"
This paper develops a test for structural monotonicity, that is, monotonicity of a structural function in an explanatory variable given any observable covariates and nonseparable time-invariant unobserved heterogeneity. We show that in a two-period panel data model, under some conditions, structural monotonicity implies shape constraints on the joint cumulative distribution function (CDF) of outcome variables conditional on the explanatory variables and covariates over specific regions. These regions are parameterized by a nuisance parameter, which can be consistently estimated. We propose a test for structural monotonicity according to the shape constraints on the conditional joint CDF over the estimated regions, and validate the empirical bootstrap method under some high-level conditions. Some Monte Carlo experiments show that the proposed test can detect departures from structural monotonicity, which are not revealed by some tests for regression monotonicity, for example tests proposed by Ghosal, Sen, and van der Vaart (2000) and Chetverikov (2017).
"A Multivariate Distribution with Pareto Tails and Pareto Maxima" (with Costas Arkolakis and Andrés Rodríguez-Clare)
We present a new multivariate distribution with Pareto distributed tails and maxima. The distribution has a number of properties that make it useful for applied work. Compared to uncorrelated univariate Pareto distributions, the distribution features one additional parameter that governs the covariance of its realizations. We show that this distribution is indeed valid by proving a general result about $n$-increasing functions.


is our elusive game.
all of her papers and pencils in the
school library. Will you help find them for her? There are
five pencils and five papers.
Directions: Use the arrow
keys to move Miley around the school
library. Once you CLICK
a paper or pencil a math problem will pop up. You have to answer
the math problem by clicking the answer at the bottom of the
page. A girl named Lilly will glide across the screen if you get
it correct. Answer all the math problems correctly to win
about this project