The next power of 2 and other tricks with logarithms

October 31, 2014
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The next power of 2 and other tricks with logarithms

The other day I was doing some computations that caused me to wonder, "What is the smallest power of 2 that is greater than a given number?" The mathematics is straightforward. Given a number n, find the least value of k such that 2k ≥ n or, equivalently, k ≥ […]

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Jobs at Amazon

October 31, 2014
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Jobs at Amazon

I do not normally post job adverts, but this was very specifically targeted to “applied time series candidates” so I thought it might be of sufficient interest to readers of this blog. Here is an excerpt from an email I received from someone at Amazon: Amazon is aggressively recruiting in the data sciences, and we […]

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Interactive plot of car crash stats

October 31, 2014
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Interactive plot of car crash stats

I spent the afternoon making a D3-based interactive version of the graphs of car crash statistics by state that I’d discussed yesterday: my attempt to improve on the graphs in Mona Chalabi‘s post at 538. See it in action here. Code on gith...

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Gaze-cueing and trustworthiness: New paper + raw data + R script on OSF

October 30, 2014
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Recently, a student of mine (Felix Süßenbach, now at the University of Edinburgh) and I published a little study on gaze-cueing, and how it is moderated by the trustworthiness of the gazing person. In a nutshell, although instructed to ignore the gaz...

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Testing……1, 2, 3, ……

October 30, 2014
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Testing……1, 2, 3, ……

I often think that most courses in econometric theory are somewhat unbalanced. Much more attention is given to estimation principles and estimator properties than is given to the principles of hypothesis testing, the properties of tests.This always str...

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Was it really necessary to do a voting experiment on 300,000 people? Maybe 299,999 would’ve been enough? Or 299,998? Or maybe 2000?

October 30, 2014
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Was it really necessary to do a voting experiment on 300,000 people?  Maybe 299,999 would’ve been enough?  Or 299,998?  Or maybe 2000?

There’s been some discussion recently about an experiment done in Montana, New Hampshire, and California, conducted by three young political science professors, in which letters were sent to 300,000 people, in order to (possibly) affect their voting behavior. It appears that the plan was to follow up after the elections and track voter turnout. (Some […] The post Was it…

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How a fraud detection algorithm conspired to ruin my recent trip

October 30, 2014
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I have been traveling quite a bit lately, and last week, I went to Rome for a few days, and spent time at the KDIR conference. Rome is one of my favorite destinations and apart from the architecture and museums, and the restaurants, I also enjoy shopping there. To my dismay, a gray cloud followed me around this entire trip…

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Bias/variance tradeoff as gamesmanship

October 30, 2014
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Bias/variance tradeoff as gamesmanship

Continuing our series of reading out loud from a single page of a statistics book we look at page 224 of the 1972 Dover edition of Leonard J. Savage’s “The Foundations of Statistics.” On this page we are treated to an example attributed to Leo A. Goodman in 1953 that illustrates how for normally distributed […] Related posts: Automatic bias…

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Statistical distribution of incomes in different countries, and a great plot

October 30, 2014
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This post is by Phil Price. This article in the New York Times is pretty good, and the graphics are excellent…especially the interactive graphic halfway down, entitled “American Incomes Are Losing Their Edge, Except at the Top” (try mousing over the gray lines and see what happens). The plot attempts to display the statistical distribution […] The post Statistical distribution…

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"Football"… I mean "soccer"… I mean "football"…

October 29, 2014
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A couple of weeks ago, I was contacted by Daniel Weitzenfeld $-$ a Chicago freelance data scientist (his own definition). Daniel got interested in modelling sports results and googled our football paper $-$ in his post here, he jokes that, be...

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Econometrics Term Test

October 29, 2014
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Econometrics Term Test

A few days ago the students in my introductory graduate Econometrics course had their mid-term test.Here's the test, and a brief solution.How did you fare?© 2014, David E. Giles

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Improved graphs of car crash stats

October 29, 2014
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Improved graphs of car crash stats

Last week, Mona Chalabi wrote an interesting post on car crash statistics by state, at fivethirtyeight.com. I didn’t like the figures so much, though. There were a number of them like this: I’m giving a talk today about data visualization [slides | github], and I thought this would make a good example, so I spent […]

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I love it when I can respond to a question with a single link

October 29, 2014
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Shira writes: This came up from trying to help a colleague of mine at Human Rights Watch. He has several completely observed variables X, and a variable with 29% missing, Y. He wants a histogram (and other descriptive statistics) of a “filled in” Y. He can regress Y on X, and impute missing Y’s from […] The post I love…

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How to use frequency analysis to crack the Cryptoquote puzzle

October 29, 2014
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How to use frequency analysis to crack the Cryptoquote puzzle

Many people enjoy solving word games such as the daily Cryptoquote puzzle, which uses a simple substitution cipher to disguise a witty or wise quote by a famous person. A common way to attack the puzzle is frequency analysis. In frequency analysis you identify letters and pairs of letters (bigrams) […]

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Calculating the sum or mean of a numeric (continuous) variable by a group (categorical) variable in SAS

Calculating the sum or mean of a numeric (continuous) variable by a group (categorical) variable in SAS

Introduction A common task in data analysis and statistics is to calculate the sum or mean of a continuous variable.  If that variable can be categorized into 2 or more classes, you may want to get the sum or mean for each class. This sounds like a simple task, yet I took a surprisingly long time […]

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Would You Like Some Hot Potatoes?

October 29, 2014
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Would You Like Some Hot Potatoes?

O.K., I know - that was a really cheap way of getting your attention.However, it worked, and this post really is about Hot Potatoes - not the edible variety, but some teaching apps. from "Half-Baked Software" here at the University of Victoria.To quote...

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Body-slam on the sister blog

October 29, 2014
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John Ahlquist and Scott Gehlbach nail it. The post Body-slam on the sister blog appeared first on Statistical Modeling, Causal Inference, and Social Science.

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reliable ABC model choice via random forests

October 28, 2014
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reliable ABC model choice via random forests

After a somewhat prolonged labour (!), we have at last completed our paper on ABC model choice with random forests and submitted it to PNAS for possible publication. While the paper is entirely methodological, the primary domain of application of ABC model choice methods remains population genetics and the diffusion of this new methodology to […]

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Why I support statisticians and their resistance to hype

October 28, 2014
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Despite Statistics being the most mature data related discipline, statisticians have not fared well in terms of being selected for funding or leadership positions in the new initiatives brought about by the increasing interest in data. Just to give one example (Jeff and Terry Speed give many more) the White House Big Data Partners Workshop  had

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Yes, I’ll help people for free but not like this!

October 28, 2014
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I received the following (unsolicited) email: Dear Sir or Madam, My name is **; I am a graduate student, working on my thesis in **. A vital part of my research is performing a joint cluster analysis of attributional and relational data on **. I have tried to collaborate with the statisticians at ** and […] The post Yes, I’ll…

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Misguided warheads in the classroom

October 28, 2014
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Misguided warheads in the classroom

Alberto Cairo just gave a wonderful talk to my workshop, in which he complains about the state of dataviz teaching. So, it's quite opportune that reader Maja Z. sent in a couple of examples from a recent course on data...

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Blue Bonnet Bayes

October 28, 2014
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Blue Bonnet Bayes

Blue Bonnet™ used to run commercials with the jingle “Everything’s better with Blue Bonnet on it.” Maybe they still do. Perhaps in reaction to knee-jerk antipathy toward Bayesian methods, some statisticians have adopted knee-jerk enthusiasm for Bayesian methods. Everything’s better with Bayesian analysis on it. Bayes makes it better, like a little dab of margarine […]

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It is the small data that matters the most

October 28, 2014
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It is the small data that matters the most

Everyone is talking about Big Data1, but it is the small data that is holding everything together. The small slowly changing reference tables are the linchpins. Unfortunately, too often politics gets in the way as those small tables, maintained by huma...

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