## R pitfalls #4: redefining the basics

December 14, 2012
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I try to be economical when writing code; for example, I tend to use single quotes over double quotes for characters because it saves me one keystroke. One area where I don’t do that is when typing TRUE and FALSE … Continue reading →

## Multisite, multivariate genetic analysis: simulation and analysis

December 13, 2012
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The email wasn’t a challenge but a simple question: Is it possible to run a multivariate analysis in multiple sites? I was going to answer yes, of course, and leave it there but it would be a cruel, non-satisfying answer. … Continue reading →

## OrgOrgChart: The Dynamic Organization of an Organization

December 13, 2012
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The Organic Organization Chart [autodeskresearch.com], developed by Justin Matejka at Autodesk Research, shows what a Human Resources manager dreams at night. The animated force-directed network diagram shows how a company's structure evolves over t...

## Puzzles of criminal justice

December 13, 2012
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Four recent news stories about crime and punishment made me realize, yet again, how little I understand all this. 1. “HSBC to Pay \$1.92 Billion to Settle Charges of Money Laundering”: State and federal authorities decided against indicting HSBC in a money-laundering case over concerns that criminal charges could jeopardize one of the world’s largest [...]

## Book review: The Signal and The Noise

December 13, 2012
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Nate Silver first attracted attention two election cycles ago with the launch of his fivethirtyeight.com website (538 is the number of electoral votes in the United States.) He makes clean charts, which I like a lot. Since that time, he has earned a platform on the New York Times website, which goes some way to explaining the vitriol hurled at him during the just-concluded election season by the right wing.…

## Nataniele Argento

December 13, 2012
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Effectively, the Italian election campaign is already in full swing, so I tried to start collecting some data to see what we are about to face. If I have time and manage to get some good data, I'll try to replicate the analysis I made for the US electi...

## Nataniele Argento

December 13, 2012
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Effectively, the Italian election campaign is already in full swing, so I tried to start collecting some data to see what we are about to face. If I have time and manage to get some good data, I'll try to replicate the analysis I made for the US electi...

## “Teaching effectiveness” as another dimension in cognitive ability

December 12, 2012
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I’m not a great teacher. I can get by because I work hard and I know a lot, and for some students my classes are just great, but it’s not a natural talent of mine. I know people who are amazing teachers, and they have something that I just don’t have. I wrote that book, [...]

## Iterated function systems and Barnsley’s fern in SAS

December 12, 2012
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Fractals. If you grew up in the 1980s or '90s and were interested in math and computers, chances are you played with computer generation of fractals. Who knows how many hours of computer time was spent computing Mandelbrot sets and Julia sets to ever-increasing resolutions? When I was a kid, [...]

## French R Conference in Lyon – call for contributions

December 12, 2012
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[of interest mostly to French and R bilinguals] La prochaine édition des Rencontres R aura lieu à Lyon en Juillet prochain. Ci-dessous, l’appel officiel à contributions. ————————————————– Appel à communication des 2èmes Rencontres R : Dans la lignée de la conférence internationale Use’R et suite à la première édition qui a eu lieu à Bordeaux […]

## Clarifying a Previous Item Response Theory Link

December 12, 2012
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I wanted to thank those of you who have emailed and commented on my last post and its Link to Item Response Theory Presentations Using R.  In the Psychometrics Centre website, it is not until Topic 7 called Unidimensional IRT models for binar...

## Mayo on S. Senn: “How Can We Cultivate Senn’s-Ability?”

December 11, 2012
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Since Stephen Senn will be leading our seminar at the LSE tomorrow morning (see PH500 page), I’m reblogging my deconstruction of his paper (“You May Believe You Are a Bayesian But You Probably Are Wrong”) from Jan.15 2012 (though not his main topic tomorrow). At the end I link to other “U-Phils” on Senn’s paper [...]

## The consulting biz

December 11, 2012
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I received the following (unsolicited) email: Hello, *** LLC, a ***-based market research company, has a financial client who is interested in speaking with a statistician who has done research in the field of Alzheimer’s Disease and preferably familiar with the SOLA and BAPI trials. We offer an honorarium of \$200 for a 30 minute [...]

## Math Talks :: Action Movies

December 11, 2012
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Jonathan Goodman gave the departmental seminar yesterday (10 Dec 2012) and I was amused by an extended analogy he made. After his (very clear) intro, he said that math talks were like action movies. The overall theorem and its applications provide th...

## Estimating Pi

December 11, 2012
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Recently I’ve been working on some jackknife and bootstrapping problems.  While working on those projects I figured it would be a fun distraction to take the process and estimate pi.  I’m sure this problem has been tackled countless times but I have never bothered to try it using a Monte Carlo approach.  Here is the [...]

## Estimating Pi

December 11, 2012
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Recently I’ve been working on some jackknife and bootstrapping problems.  While working on those projects I figured it would be a fun distraction to take the process and estimate pi.  I’m sure this problem has been tackled countless times but I have never bothered to try it using a Monte Carlo approach.  Here is the [...]

## Linear Models with Multiple Fixed Effects

December 11, 2012
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$Linear Models with Multiple Fixed Effects$

Estimating a least squares linear regression model with fixed effects is a common task in applied econometrics, especially with panel data. For example, one might have a panel of countries and want to control for fixed country factors. In this case the researcher will effectively include this fixed identifier as a factor variable, and then proceed to […]

## How to test XCOM “dice rolls” for fairness

December 11, 2012
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XCOM: Enemy Unknown is a turn based video game where the player choses among actions (for example shooting an alien) that are labeled with a declared probability of success. Image copyright Firaxis Games A lot of gamers, after missing a 80% chance of success shot, start asking if the game’s pseudo random number generator is [...] Related posts: Statistics to English Translation, Part 2a: ’Significant’ Doesn’t Always Mean ’Important’ Statistics…

## Steroids in baseball and extremes in climate

December 11, 2012
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One of my friends pointed out this video to me. I realize this is not new, but it is still worth watching… Thanks to Jeff Masters, Anthony Broccoli, and other researchers who have introduced the “weather on steroids” analogy to the climate science community and Noah Besser who produced a video to explain the interesting analogy that involves […]

## There are four ways to get fired from Caesars: (1) theft, (2) sexual harassment, (3) running an experiment without a control group, and (4) keeping a gambling addict away from the casino

December 11, 2012
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Ever since I got this new sound system for my bike, I’ve been listening to a lot of podcasts. This American Life is really good. I know, I know, everybody knows that, but it’s true. The only segments I don’t like are the ones that are too “writerly,” when they read a short story aloud. [...]

## Bomb Sight: Mapping the WW2 Bombs that Fell on London during The Blitz

December 11, 2012
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7 September 1940 was the start of the The Blitz, the sustained strategic bombing of the United Kingdom by Germany during the Second World War. London was bombed by the Luftwaffe for 57 consecutive nights. More than one million London houses were destr...

## Comparing regions: maps, cartograms and tree maps

December 11, 2012
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Last week I attended a seminar where a talk was given about the economic opportunities in the SAAAME (South-America, Asia, Africa and Middle East) regions. Of course a map was shown with those regions highlighted. The map was not that disimilar to the ...

## Kaggle Digit Recoginizer: SAS k-Nearest Neighbor solution

December 11, 2012
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Kaggle is hosting an educational data mining competition: Kaggle Digit Recognizer, using MNIST data. Handwritten digit recognition is one of the few applications that kNN classifier performs well. Of course, the benchmark kNN classifier provided by the...