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Invasive Species, PTAs and Fantasy Football (Statshot)

The U.S. government is fighting several introduced animal species that are crowding out natives. The number of nonprofits supporting U.S. public schools grew sharply between 1995 and 2010. Last weekend, the Pittsburgh Steelers’ Ben Roethlisberger earned the fifth-highest fantasy point total by a quarterback in the past 10 years.

Belphegor Primes

Belphegor is one of the Seven Princes of Hell, charged with helping people make ingenious inventions and discoveries. Simon Singh gave the name Belphegor’s Prime to the number 1000000000000066600000000000001, which is the Number of the Beast, 666, from the Apocalypse, surrounded on each side by an unlucky 13 zeroes. Generally, Belphegor numbers Bn = (10^(n+3) […]

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. Show More Summary

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

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). Show More Summary

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

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. Show More Summary

Kloosterman paths

It was almost twenty years ago that I started drawing and looking at the graphs of Kloosterman sums (at least, that’s a likely date; I don’t remember when it began, but I put some drawings as whimsical illustrations — see, e.g., page 26 — in my PhD thesis to enliven it, and that was around […]

Body-slam on the sister blog

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.

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

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 . Show More Summary

And sometimes they don’t spam you at all

I received the following email: Dear Dr. Gelman, As a way of introduction, my name is... and I am very interested in studying in Columbia’s PhD statistics program. For the past 2 ½ years, I’ve worked as an analyst for... I am writing...Show More Summary

2 on chess

Is it really “often easier to win a rematch than to defend a championship”? The quoted bit above comes from Tyler Cowen, writing about the Anand/Carlsen world championship rematch. I’m still not used to the idea of a new world championship match every year but I guess why not? Anyway, here’s my question. Show More Summary

Number Of Divisors In A Range

We have today an interview question that was posted to the internet by a candidate who didn’t get the job, and wondered what he had done wrong. I’ll paraphrase his question: The interview question was to find the number of integers between x and y that are divisible by n; you may assume that x, […]

The Elliott-Halberstam conjecture implies the Vinogradov least quadratic nonresidue conjecture

I’ve just uploaded to the arXiv my paper “The Elliott-Halberstam conjecture implies the Vinogradov least quadratic nonresidue conjecture“. As the title suggests, this paper links together the Elliott-Halberstam conjecture from sieve theory with the conjecture of Vinogradov concerning the least quadratic nonresidue of a prime. Show More Summary


Yesterday my younger son was playing dice; the game involved throwing 6 dices simultaneously, and he threw a complete set 1, 2, 4, 5, 6, twice in a row! Is that a millenial-style coincidence worth cosmic pronouncements? Actually, not that much: since the dices are indistinguishable, the probability of a single throw of this type […]

On deck this week

Mon: 2 on chess Tues: Yes, I’ll help people for free but not like this! Wed: I love it when I can respond to a question with a single link Thurs: Boo! Who’s afraid of availability bias? Fri: This is where they publish the stuff that’s...Show More Summary

Solution to the sample-allocation problem

See this recent post for background. Here’s the question: You are designing an experiment where you are estimating a linear dose-response pattern with a dose that x can take on the values 1, 2, 3, and the response is continuous. Suppose that there is no systematic error and that the measurement variance is proportional to x. Show More Summary

'Competing Foundations?' Conference

FINAL CFP and EXTENDED DEADLINE: SoTFoM II `Competing Foundations?', 12-13 January 2015, London. The focus of this conference is on different approaches to the foundations of mathematics. The interaction between set-theoretic and category-theoretic foundations has had significant philosophical impact, and...

A Banach algebra proof of the prime number theorem

The prime number theorem can be expressed as the assertion as, where is the von Mangoldt function. It is a basic result in analytic number theory, but requires a bit of effort to prove. One “elementary” proof of this theorem proceeds through the Selberg symmetry formula where the second von Mangoldt function is defined […]

Solution to the problem on the distribution of p-values

See this recent post for background. Here’s the question: It is sometimes said that the p-value is uniformly distributed if the null hypothesis is true. Give two different reasons why this statement is not in general true. The problem...Show More Summary

More Tornadoes Recorded Doesn’t Mean More Tornadoes Occurring

The number of tornadoes recorded by the National Climatic Data Center has increased in recent years, but that doesn’t mean there have been more twisters.

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