PhilStat/Law: Nathan Schachtman: Acknowledging Multiple Comparisons in Statistical Analysis: Courts Can and Must

October 19, 2014
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The following is from Nathan Schachtman’s legal blog, with various comments and added emphases (by me, in this color). He will try to reply to comments/queries. “Courts Can and Must Acknowledge Multiple Comparisons in Statistical Analyses” Nathan Schachtman, Esq., PC * October 14th, 2014 In excluding the proffered testimony of Dr. Anick Bérard, a Canadian perinatal […]

Hoe noem je?

October 18, 2014
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Haynes Goddard writes: Reviewing my notes and books on categorical data analysis, the term “nominal” is widely employed to refer to variables without any natural ordering. I was a language major in UG school and knew that the etymology of nominal is the Latin word nomen (from the Online Etymological Dictionary: early 15c., “pertaining to […] The post Hoe noem je? appeared first on Statistical Modeling, Causal Inference, and Social…

Econometric Research Resources

October 17, 2014
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The following page, put together by John Kane at the Department of Economics, SUNY-Oswego, has some very useful links for econometrics students and researchers: Econometric Research Resources. © 2014, David E. Giles

Bayes Rule in an animated gif

October 17, 2014
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Say Pr(A)=5% is the prevalence of a disease (% of red dots on top fig). Each individual is given a test with accuracy Pr(B|A)=Pr(no B| no A) = 90% .  The O in the middle turns into an X when the test fails. The rate of Xs is 1-Pr(B|A). We want to know the probability

How do companies use Bayesian methods?

October 17, 2014
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Jason May writes: I’m in Northwestern’s Predictive Analytics grad program. I’m working on a project providing Case Studies of how companies use certain analytic processes and want to use Bayesian Analysis as my focus. The problem: I can find tons of work on how one might apply Bayesian Statistics to different industries but very little […] The post How do companies use Bayesian methods? appeared first on Statistical Modeling, Causal…

Wolfram’s Rule 30 in SAS

October 17, 2014
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My previous blog post describes how to implement Conway's Game of Life by using the dynamically linked graphics in SAS/IML Studio. But the Game of Life is not the only kind of cellular automata. This article describes a system of cellular automata that is known as Wolfram's Rule 30. In […]

Creating the field of evidence based data analysis – do people know what a p-value looks like?

October 16, 2014
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In the medical sciences, there is a discipline called "evidence based medicine". The basic idea is to study the actual practice of medicine using experimental techniques. The reason is that while we may have good experimental evidence about specific medicines or practices, the global behavior and execution of medical practice may also matter. There have been

Prediction Market Project for the Reproducibility of Psychological Science

October 16, 2014
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Anna Dreber Almenberg writes: The second prediction market project for the reproducibility project will soon be up and running – please participate! There will be around 25 prediction markets, each representing a particular study that is currently being replicated. Each study (and thus market) can be summarized by a key hypothesis that is being tested, which […] The post Prediction Market Project for the Reproducibility of Psychological Science appeared first on…

Dear Laboratory Scientists: Welcome to My World

October 15, 2014
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Consider the following question: Is there a reproducibility/replication crisis in epidemiology? I think there are only two possible ways to answer that question: No, there is no replication crisis in epidemiology because no one ever believes the result of an epidemiological study unless it has been replicated a minimum of 1,000 times in every possible

Beware Graphical Networks from Rating Scales without Concrete Referents

October 15, 2014
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We think of latent variables as hidden causes for the correlations among observed measures and rely on factor analysis to reveal the underlying structure. In a previous post, I borrowed an alternative metaphor from the R package qgraph and produce...

a bootstrap likelihood approach to Bayesian computation

October 15, 2014
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This paper by Weixuan Zhu, Juan Miguel Marín [from Carlos III in Madrid, not to be confused with Jean-Michel Marin, from Montpellier!], and Fabrizio Leisen proposes an alternative to our 2013 PNAS paper with Kerrie Mengersen and Pierre Pudlo on empirical likelihood ABC, or BCel. The alternative is based on Davison, Hinkley and Worton’s (1992) […]

Statistical Communication and Graphics Manifesto

October 15, 2014
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Statistical communication includes graphing data and fitted models, programming, writing for specialized and general audiences, lecturing, working with students, and combining words and pictures in different ways. The common theme of all these interactions is that we need to consider our statistical tools in the context of our goals. Communication is not just about conveying […] The post Statistical Communication and Graphics Manifesto appeared first on Statistical Modeling, Causal Inference,…

My course on Statistical Communication and Graphics

October 15, 2014
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We will study and practice many different aspects of statistical communication, including graphing data and fitted models, programming in Rrrrrrrr, writing for specialized and general audiences, lecturing, working with students and colleagues, and combining words and pictures in different ways. You learn by doing: each week we have two classes that are full of student […] The post My course on Statistical Communication and Graphics appeared first on Statistical Modeling,…

The Fault in Our Stars: It’s even worse than they say

October 15, 2014
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In our recent discussion of publication bias, a commenter link to a recent paper, “Star Wars: The Empirics Strike Back,” by Abel Brodeur, Mathias Le, Marc Sangnier, Yanos Zylberberg, who point to the notorious overrepresentation in scientific publications of p-values that are just below 0.05 (that is, just barely statistically significant at the conventional level) […] The post The Fault in Our Stars: It’s even worse than they say appeared…

October 15, 2014
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I had the pleasure of visiting the Facebook data science team last week, and we spent some time chatting about visual communication, something they care as much about as I do. Solomon reported about our conversation in this blog post....

A short taxonomy of Bayes factors

October 15, 2014
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[Update Oct 2014: Due to some changes to the Bayes factor calculator webpage, and as I understand BFs much better now, this post has been updated ...] I started to familiarize myself with Bayesian statistics. In this post I’ll show some insights ...

Cellular automata and the Game of Life in SAS

October 15, 2014
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A colleague jokingly teases me whenever I write a blog that demonstrates how to write fun and exciting programs by using SAS software. "Why do you get to have all the fun?" he mock-chides. Today I'm ready to face his ribbing, because this article is about Conway's Game of Life […]

Loi multinomiale et loi du chi-deux

October 15, 2014
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$\boldsymbol{N}=(N_{1},\cdots,N_{k})$

La semaine passée, en cours, j’avais rappelé que quand décrivait le compte de  variable multinomiales prenant modalités, la variable suit asymptotiquement une loi . Et plus généralement, on peut montrer que . Le soucis est que la matrice de variance covariance n’est pas la matrice identité. Pire que ça, elle n’est pas diagonale. Encore pire, elle n’est pas inversible. On ne peut alors pas utiliser le joli résultat qui nous…

Congratulations to Dr Souhaib Ben Taieb

October 15, 2014
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Souhaib Ben Taieb has been awarded his doctorate at the Université libre de Bruxelles and so he is now officially Dr Ben Taieb! Although Souhaib lives in Brussels, and was a student at the Université libre de Bruxelles, I co-supervised his doctorate (along with Professor Gianluca Bontempi). Souhaib is the 19th PhD student of mine to […]

I didn’t say that! Part 2

October 14, 2014
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Uh oh, this is getting kinda embarrassing. The Garden of Forking Paths paper, by Eric Loken and myself, just appeared in American Scientist. Here’s our manuscript version (“The garden of forking paths: Why multiple comparisons can be a problem, even when there is no ‘fishing expedition’ or ‘p-hacking’ and the research hypothesis was posited ahead […] The post I didn’t say that! Part 2 appeared first on Statistical Modeling, Causal…

1 in 5 million

October 14, 2014
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Earlier today, I've got an email from UCL Library Services, telling me that our research publications repository (UCL Discovery) has "recently passed the exciting milestone of 5 million downloads".As it happens, the 5 million-th download was our paper ...

Operate on the body of a file but not the header

October 14, 2014
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Sometimes you need to run some UNIX command on a file but only want to operate on the body of the file, not the header. Create a file called body somewhere in your \$PATH, make it executable, and add this to it:#!/bin/bashIFS= read -r headerprintf '%s\n...

In one of life’s horrible ironies, I wrote a paper “Why we (usually) don’t have to worry about multiple comparisons” but now I spend lots of time worrying about multiple comparisons

October 14, 2014
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Exhibit A: [2012] Why we (usually) don’t have to worry about multiple comparisons. Journal of Research on Educational Effectiveness 5, 189-211. (Andrew Gelman, Jennifer Hill, and Masanao Yajima) Exhibit B: The garden of forking paths: Why multiple comparisons can be a problem, even when there is no “fishing expedition” or “p-hacking” and the research hypothesis […] The post In one of life’s horrible ironies, I wrote a paper “Why we…