Blog Archives

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
By
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 really necessary to do a voting experiment on 300,000 people?…

Read more »

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

October 29, 2014
By

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 it when I can respond to a question with a…

Read more »

Body-slam on the sister blog

October 29, 2014
By

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.

Read more »

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

October 28, 2014
By

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 help people for free but not like this! appeared first…

Read more »

And sometimes they don’t spam you at all

October 28, 2014
By

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 to communicate my interest in your […] The post And sometimes they don’t spam you at all appeared first on Statistical…

Read more »

2 on chess

October 27, 2014
By
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. Tyler Cowen […] The post 2 on chess appeared first on Statistical Modeling, Causal Inference, and Social…

Read more »

On deck this week

October 27, 2014
By

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: Sokal: “science is not merely a bag of clever tricks . . . Rather, the natural sciences are nothing more or less than one […] The post On deck this week appeared first on Statistical Modeling, Causal Inference, and…

Read more »

Solution to the sample-allocation problem

October 26, 2014
By

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. You […] The post Solution to the sample-allocation problem appeared first on Statistical Modeling, Causal Inference,…

Read more »

Solution to the problem on the distribution of p-values

October 25, 2014
By

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 is with real examples, not just toy examples, so your reasons should not involve degenerate situations such as […] The post Solution to the problem on the distribution of p-values appeared first on…

Read more »

Solution to the helicopter design problem

October 24, 2014
By

See yesterday’s post for background. Here’s the question: In the helicopter activity, pairs of students design paper ”helicopters” and compete to create the copter that takes longest to reach the ground when dropped from a fixed height. The two parameters of the helicopter, a and b, correspond to the length of certain cuts in the […] The post Solution to the helicopter design problem appeared first on Statistical Modeling, Causal…

Read more »


Subscribe

Email:

  Subscribe