## What does a Bayes factor feel like?

January 30, 2015
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A Bayes factor (BF) is a statistical index that quantifies the evidence for a hypothesis, compared to an alternative hypothesis (for introductions to Bayes factors, see here, here or here). Although the BF is a continuous measure of evidence, humans lo...

## The snow made me do it – California, here I come

January 29, 2015
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California readers: here's a chance to come meet me. I am giving talks in San Diego (Feb 3) and San Mateo (Feb 5) next week, courtesy of JMP. Free registration is here. These talks are related to two ongoing projects...

## Six quick tips to improve your regression modeling

January 29, 2015
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It’s Appendix A of ARM: A.1. Fit many models Think of a series of models, starting with the too-simple and continuing through to the hopelessly messy. Generally it’s a good idea to start simple. Or start complex if you’d like, but prepare to quickly drop things out and move to the simpler model to help […] The post Six quick tips to improve your regression modeling appeared first on Statistical…

## Three short lessons on comparisons

January 29, 2015
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I like this New York Times graphic illustrating the (over-the-top) reaction by the New York police to the Eric Garner-inspired civic protests during the holidays. This is a case where the data told a story that mere eyes and ears...

## First day of class update

January 29, 2015
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I got to class on time. The class went ok but I spent too much time talking, which is what happens when I don’t put a lot of effort ahead of time into making sure I don’t spend too much time talking. My first-day-of-class activity was ok but I think I needed another activity for […] The post First day of class update appeared first on Statistical Modeling, Causal Inference,…

## From Markdown to LaTeX output using RMarkdown.

January 28, 2015
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I’ve been working on the ggRandomForests vignettes pretty consistently now. I’m writing the randomForestSRC-Survival vignette in LaTeX with the knitr vignette engine. I wrote the the randomForestSRC-Regression vignette in markdown. I’ve decided to upload the Regression vignette to arXiv for… Continue reading →

## Link: Tapestry 2015

January 28, 2015
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Tapestry 2015 will take place March 4 in Athens, GA. This is the third time we are holding the conference, and it is again taking place on the day before NICAR. As in the past years, have a kick-ass line-up of speakers. The keynotes will be given by Hannah Fairfield (NY Times), Kim Rees (Periscopic), and … Continue reading Link: Tapestry 2015

## Just in case

January 28, 2015
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Hi, R. Could you please prepare 50 handouts of the attached draft course plan (2-sided printing is fine) to hand out to students? I prefer to do this online but it sounds like there’s some difficulty with that, so we can do handouts on this first day of class. Also: My Amtrak is rescheduled and […] The post Just in case appeared first on Statistical Modeling, Causal Inference, and Social…

## Just in case

January 28, 2015
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Hi, R. Could you please prepare 50 handouts of the attached draft course plan (2-sided printing is fine) to hand out to students? I prefer to do this online but it sounds like there’s some difficulty with that, so we can do handouts on this first day of class. Also: My Amtrak is rescheduled and […] The post Just in case appeared first on Statistical Modeling, Causal Inference, and Social…

## Probability approximations

January 28, 2015
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This week’s resource post lists notes on probability approximations. Do we even need probability approximations anymore? They’re not as necessary for numerical computation as they once were, but they remain vital for understanding the behavior of probability distributions and for theoretical calculations. Textbooks often leave out details such as quantifying the error when discussion approximations. The […]

## The relationship between skewness and kurtosis

January 28, 2015
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In my book Simulating Data with SAS, I discuss a relationship between the skewness and kurtosis of probability distributions that might not be familiar to some statistical programmers. Namely, the skewness and kurtosis of a probability distribution are not independent. If κ is the full kurtosis of a distribution and […]

## 3 YEARS AGO: (JANUARY 2012) MEMORY LANE

January 28, 2015
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MONTHLY MEMORY LANE: 3 years ago: January 2012. I mark in red three posts that seem most apt for general background on key issues in this blog. January 2012 (1/3) Model Validation and the LLP-(Long Playing Vinyl Record) (1/8) Don’t Birnbaumize that Experiment my Friend* (1/10) Bad-Faith Assertions of Conflicts of Interest?* (1/13) U-PHIL: “So you want to do a philosophical analysis?” (1/14) “You May Believe You […]

## About a zillion people pointed me to yesterday’s xkcd cartoon

January 27, 2015
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I have the same problem with Bayes factors, for example this: and this: (which I copied from Wikipedia, except that, unlike you-know-who, I didn’t change the n’s to d’s and remove the superscripting). Either way, I don’t buy the numbers, and I certainly don’t buy the words that go with them. I do admit, though, […] The post About a zillion people pointed me to yesterday’s xkcd cartoon appeared first…

## Crowdsourcing data analysis: Do soccer referees give more red cards to dark skin toned players?

January 27, 2015
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Raphael Silberzahn Eric Luis Uhlmann Dan Martin Pasquale Anselmi Frederik Aust Eli Christopher Awtrey Štěpán Bahník Feng Bai Colin Bannard Evelina Bonnier Rickard Carlsson Felix Cheung Garret Christensen Russ Clay Maureen A. Craig Anna Dalla Rosa Lammertjan Dam Mathew H. Evans Ismael Flores Cervantes Nathan Fong Monica Gamez-Djokic Andreas Glenz Shauna Gordon-McKeon Tim Heaton Karin […] The post Crowdsourcing data analysis: Do soccer referees give more red cards to dark…

## Check your return types when modeling in R

January 27, 2015
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Just a warning: double check your return types in R, especially when using different modeling packages. We consider ourselves pretty familiar with R. We have years of experience, many other programming languages to compare R to, and we have taken Hadley Wickham’s Master R Developer Workshop (highly recommended). We already knew R’s predict function is … Continue reading Check your return types when modeling in R → Related posts: R…

## Light entertainment: collector’s T-shirts

January 27, 2015
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Chuck P. sent me this little amusement. Some other good stuff on here.

## Limits of statistics, and by extension data science, as illustrated by Deflate-gate

January 27, 2015
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A number of readers sent me Warren Sharp's piece about the ongoing New England Patriots' deflate-gate scandal (link to Slate's version of this) so I suppose I should say something about it. For those readers who are not into American football, the Superbowl is soon upon us. New England, one of the two finalists, has been accused of using footballs that are below the weight requirements on the rulebook, hence…

## More data, less accuracy

January 27, 2015
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Statistical methods should do better with more data. That’s essentially what the technical term “consistency” means. But with improper numerical techniques, the the numerical error can increase with more data, overshadowing the decreasing statistical error. There are three ways Bayesian posterior probability calculations can degrade with more data: Polynomial approximation Missing the spike Underflow Elementary numerical integration algorithms, […]

## “It is perhaps merely an accident of history that skeptics and subjectivists alike strain on the gnat of the prior distribution while swallowing the camel that is the likelihood”

January 27, 2015
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I recently bumped into this 2013 paper by Christian Robert and myself, “‘Not Only Defended But Also Applied': The Perceived Absurdity of Bayesian Inference,” which begins: Younger readers of this journal may not be fully aware of the passionate battles over Bayesian inference among statisticians in the last half of the twentieth century. During this […] The post “It is perhaps merely an accident of history that skeptics and subjectivists…

## googleVis version 0.5.8 released

January 27, 2015
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We released googleVis version 0.5.8 on CRAN last week. The update is a maintenance release for the forthcoming release of R 3.2.0. Screen shot of some of the Google ChartsNew to googleVis? The package provides an interface between R and the Google Char...

## Trial on Anil Potti’s (clinical) Trial Scandal Postponed Because Lawyers Get the Sniffles (updated)

January 27, 2015
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Trial in Medical Research Scandal Postponed By Jay Price DURHAM, N.C. — A judge in Durham County Superior Court has postponed the first civil trial against Duke University by the estate of a patient who had enrolled in one of a trio of clinical cancer studies that were based on bogus science. The case is […]

## the density that did not exist…

January 26, 2015
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$the density that did not exist…$

On Cross Validated, I had a rather extended discussion with a user about a probability density as I thought it could be decomposed in two manageable conditionals and simulated by Gibbs sampling. The first component led to a Gumbel like density wirh y being restricted to either (0,1) or (1,∞) depending on β. The density […]

## Reproducible Research Course Companion

January 26, 2015
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I'm happy to announce that you can now get a copy of the Reproducible Research Course Companion from the Apple iBookstore. The purpose of this e-book is pretty simple. The book provides all of the key video lectures from my Reproducible Research course offered on Coursera, in a simple offline e-book format. The book can be viewed