Comments on: Small samples, and the margin of error

By: Terence Tao

Terence Tao — Mon, 26 Sep 2011 03:25:01 +0000

Yes, the 95% probability only applies as an unconditional probability before the poll is taken, and not as a conditional probability after the poll is taken; this is discussed at the end of the “Assumptions and conclusions” section.

By: xoeve

xoeve — Sun, 25 Sep 2011 15:08:05 +0000

This isn’t true. The 95% probability refers to the sampling error, not to the interval itself. The true population percentage is either in the interval or it is not. If we conducted the same survey many times, drawing a new sample each time, and we calculated the 95% confidence interval around the estimated proportion in each of these, then we would have many confidence intervals. 95% of these would contain the true population percentage, 5% would not.

By: Quora

Quora — Sat, 30 Jul 2011 07:40:50 +0000

How do I determine that there are less than 10% brown M&Ms in a particular group?…

The fact that the big box is 20% brown doesn’t have any bearing — you could break the box up into groups in such a way that one of the groups was entirely brown, or such that one group was entirely red, or both. In fact, since you’re only looking at…

By: A second draft of a non-technical article on universality « What’s new

Wed, 15 Sep 2010 06:15:25 +0000

[...] Tao, “Small samples and the margin of error“, blog post, [...]

By: April S.

April S. — Wed, 11 Aug 2010 17:43:58 +0000

This is a really interesting! I love statistics and hate it when I see polls that are obviously skewed in their results. I think a big part of it is biased sampling. Poll the people who will give the answer you want and most people don’t know the difference!

http://blog.thinkwell.com/2010/08/7th-grade-math-populations-and-samples.html

By: Mike

Mike — Tue, 13 Oct 2009 18:25:06 +0000

Nice to look back at somthing written before the elections. Thanks

By: Benford’s law, Zipf’s law, and the Pareto distribution « What’s new

Sat, 04 Jul 2009 04:10:36 +0000

[...] the CIA world factbook); I have put the raw data here. This is a relatively small sample (cf. my previous post), but is already enough to discern these laws in action. For instance, here is how the data set [...]

By: balkrishnapatankar

balkrishnapatankar — Mon, 22 Dec 2008 18:24:31 +0000

Thanks … Very interesting article …. Please keep writing more of such non technical but a bit mathematical posts in future

By: Margin of Error « I’m just a simple DBA on a complex production system

Wed, 19 Nov 2008 05:43:22 +0000

[...] you are really interested in the subject and not afraid of some mathematical notation, Terence Tao has a much deeper analysis of the subject. [...]

By: How Polling Works « Curious Ramblings

How Polling Works « Curious Ramblings — Fri, 14 Nov 2008 05:28:11 +0000

[...] Polling Works Terrence Tao has a great blog entry about the mathematics of polling. One thing he points out, which to me at first was unintuitive, is that polling accuracy is [...]