Try This Problem

September 21, 2015
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Try This Problem

Here's a little exercise for you to work on:We know from the Gauss-Markhov Theorem that within the class of linear and unbiased estimators, the OLS estimator is most efficient. Because it is unbiased, it therefore has the smallest possible Mean Squared...

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Have weak data. But need to make decision. What to do?

September 21, 2015
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Vlad Malik writes: I just re-read your article “Of Beauty, Sex and Power”. In my line of work (online analytics), low power is a recurring, existential problem. Do we act on this data or not? If not, why are we even in this business? That’s our daily struggle. Low power seems to create a sort […] The post Have weak data. But need to make decision. What to do? appeared…

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Statbusters: What the experiments on rigging elections via Google tell us

September 21, 2015
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For this week's Statbusters (link), we opine on that astounding report from a few weeks ago about how Google could manipulate the next elections by biasing search results. We walk you through our vetting process, starting with face validity ("the magnitude of the reported effect is too large to be believed!"). The crux of the article is about the experimental design. You start with a group of people who have…

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Making stuff up to get published in NYTimes

September 21, 2015
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Making stuff up to get published in NYTimes

Reader/friend Tom B. knows about my interest in grade "deflation" policies, and proceeds to ruin my breakfast by sending me a link to this ludicrous "letter to the editor" by a high-school counsellor (link). It starts with a made-up assertion: As the new academic term starts, I’m rooting for this to be the year when students start getting the grades they rightfully earn without high schools and colleges manipulating numbers…

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On deck this week

September 21, 2015
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Mon: Have weak data. But need to make decision. What to do? Tues: “I do not agree with the view that being convinced an effect is real relieves a researcher from statistically testing it.” Wed: Optimistic or pessimistic priors Thurs: Draw your own graph! Fri: Low-power pose Sat: Annals of Spam Sun: The Final Bug, […] The post On deck this week appeared first on Statistical Modeling, Causal Inference, and…

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Nice title but dubious message

September 21, 2015
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Nice title but dubious message

I like to uaeuse declarative titles for charts. This chart below, found in an investment magazine published by Charles Schwab, wants to tell us that emerging markets "perform differently." That is a nice concise message. Now, what does the chart...

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International Symposium on Forecasting: Spain 2016

September 21, 2015
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International Symposium on Forecasting: Spain 2016

June 19-22, 2016 Santander, Spain – Palace of La Magdalena The International Symposium on Forecasting (ISF) is the premier forecasting conference, attracting the world’s leading forecasting researchers, practitioners, and students. Through a combination of keynote speaker presentations, academic sessions, workshops, and social programs, the ISF provides many excellent opportunities for networking, learning, and fun. Speakers: […]

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Excluding variables: Read all but one variable into a matrix

September 21, 2015
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Excluding variables: Read all but one variable into a matrix

Dear Rick, I have a data set with 1,001 numerical variables. One variable is the response, the others are explanatory variable. How can I read the 1,000 explanatory variables into an IML matrix without typing every name? That's a good question. You need to be able to perform two sub-tasks: […] The post Excluding variables: Read all but one variable into a matrix appeared first on The DO Loop.

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Erdos bio for kids

September 20, 2015
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Chris Gittins recommends the book, “The Boy Who Loved Math: The Improbable Life of Paul Erdos,” by Deborah Heiligman. Gittins reports: We read it with our soon-to-be-first-grader this evening. She liked it and so did we. I knew a little about Erdos but the book probably quadrupled my knowledge. Thought it might be of interest […] The post Erdos bio for kids appeared first on Statistical Modeling, Causal Inference, and…

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Recipe for Computing and Sampling Multivariate Kernel Density Estimates (and Plotting Contours for 2D KDEs).

September 19, 2015
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Recipe for Computing and Sampling Multivariate Kernel Density Estimates (and Plotting Contours for 2D KDEs).

The code snippet below creates the above graphic: ## radially symmetric kernel (Gussian kernel) RadSym

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“The frequentist case against the significance test”

September 19, 2015
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Richard Morey writes: I suspect that like me, many people didn’t get a whole lot of detail about Neyman’s objections to the significance test in their statistical education besides “Neyman thought power is important”. Given the recent debate about significance testing, I have gone back to Neyman’s papers and tried to summarize, for the modern […] The post “The frequentist case against the significance test” appeared first on Statistical Modeling,…

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Predicting Titanic deaths on Kaggle VI: Stan

September 19, 2015
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It is a bit a contradiction. Kaggle provides competitions on data science, while Stan is clearly part of the (Bayesian) statistics. Yet after using random forests, boosting and bagging, I also think this problem has a suitable size for Stan, which I un...

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Stan users meetup in Cambridge, MA on 9/22

September 19, 2015
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There’s a new Stan users meetup group in Boston / Camberville. The first meeting will be on Tuesday, 9/22, at 6 pm in Cambridge. If you’re a seasoned Stan user, just starting out with Stan, or hearing about Stan for the first time, feel free to join in. At least a couple of the Stan […] The post Stan users meetup in Cambridge, MA on 9/22 appeared first on Statistical…

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The Leek group guide to writing your first paper

September 18, 2015
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The @jtleek guide to writing your first academic paper https://t.co/APLrEXAS46 — Stephen Turner (@genetics_blog) September 17, 2015 I have written guides on reviewing papers, sharing data,  and writing R packages. One thing I haven't touched on until now has been writing papers. Certainly for me, and I think for a lot of students, the hardest

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Unreplicable

September 18, 2015
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Leonid Schneider writes: I am cell biologist turned science journalist after 13 years in academia. Despite my many years experience as scientist, I shamefully admit to be largely incompetent in statistics. My request to you is as follows: A soon to be published psychology study set on to reproduce 100 randomly picked earlier studies and […] The post Unreplicable appeared first on Statistical Modeling, Causal Inference, and Social Science.

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I’m speaking in Germany today!

September 18, 2015
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I’m speaking in Germany today!

Right between Mittagspause and Tagungsabschluss, just how I like it. It’s a methods conference for the German Psychological Society in Jena. Here’s my title and abstract: Applied Bayesian Statistics Bayesian methods allow the smooth combination of information from multiple sources and are associated with open acknowledgement about uncertainty. We discuss modern applied Bayesian perspectives on […] The post I’m speaking in Germany today! appeared first on Statistical Modeling, Causal Inference,…

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Petit exercice de proba

September 17, 2015
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Petit exercice de proba

Mardi dernier, on avait fait une série d’exercices de proba, et je voulais reprendre un exercice pour lequel j’avais proposé une vérification sur ordinateur. Pour résoudre l’exercice, j’avais suggéré la méthode suivante. est tiré parmi , alors que est tiré parmi .  On note assez facilement que le plus petit nombre est , et comme le ppcm de  et  est , (je laisse faire les calculs pour montrer qu’effectivement, au delà, on n’est plus dans les ensembles…

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Not So Standard Deviations: The Podcast

September 17, 2015
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I'm happy to announce that I've started a brand new podcast called Not So Standard Deviations with Hilary Parker at Etsy. Episode 1 "RCatLadies Origin Story" is available through SoundCloud. In this episode we talk about the origins of RCatLadies, evidence-based data analysis, my new book, and the Python vs. R debate. You can subscribe

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The Map of Romantic Kissing with Leaflet and R

September 17, 2015
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The Map of Romantic Kissing with Leaflet and R

Romantic kissing is a cultural universal, right? Nope! At least not if you are to believe Jankowiak et al. (2015) who surveyed a large number of cultures and found that “sexual-romantic kissing” occurred in far from all of them. For some reasons ...

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Medical decision making under uncertainty

September 17, 2015
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Gur Huberman writes: The following crossed my mind, following a recent panel discussion in which David Madigan participated on evidence-based medicine. The panel—especially John Iaonnidis—sang the praise of clinical trials. You may have nothing wise to say about it—or pose the question to your blog followers. Suppose there’s a standard clinical procedure to address a […] The post Medical decision making under uncertainty appeared first on Statistical Modeling, Causal Inference,…

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imager now on CRAN, and a non-linear filtering example

September 17, 2015
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imager now on CRAN, and a non-linear filtering example

imager is an R package for image processing that’s fairly fast and now quite powerful (if I may say so myself). It wraps a neat C++ library called CImg, by David Tschumperlé (CNRS). It took quite a bit of work, but imager is now on CRAN, so that installing it is as easy as: Here’s […]

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The aching desire for regular scientific breakthroughs

September 16, 2015
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The aching desire for regular scientific breakthroughs

This post didn’t come out the way I planned. Here’s what happened. I cruised over to the British Psychological Society Research Digest (formerly on our blogroll) and came across a press release entitled “Background positive music increases people’s willingness to do others harm.” Uh oh, I thought. This sounds like one of those flaky studies, […] The post The aching desire for regular scientific breakthroughs appeared first on Statistical Modeling,…

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Warning Problem Hopefully Solved

September 16, 2015
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If during the last month you got a warning when accessing No Hesitations, I may have found and fixed the problem, finally.  (This happened once before.)  There were a couple of clearly bogus comments, which contained links that may have ...

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