Re: Anyone good at statistics...??

On Tue, 1 Sep 2009 21:03:18 +0100, "Manx" <Manx@xxxxxxxxxxxxxx> wrote:

Hi foks.

Just wondering about all those surveys that ask hundreds or thousands of
people what they think of Darwinism, Creationism, etc: I'm told that when
the figures are extrapolated to produce an estimate for the entire
population, there's some kind of 'confidence level' that can be calculated
from the size of the sample.

Is this right so far...?

So... what can a survey say if only *three people* were asked? What does the
statistical analysis say that makes it clear to everyone that three is a
lousy number of people to ask...? Hoe does the 'three-ness' of your survey
show up in your final results?

Does my question make sense...?

Ta for all thoughts!

M.

This is a well worked out problem in sampling. See, for example,
Margin of Error and Confidence Levels Made Simple
http://www.isixsigma.com/library/content/c040607a.asp

which has a table of percent margin of error (at the 95% confidence
level) vs. sample size. A sample size of 50 has a margin of error of
14% and the error grows very rapidly for smaller sample sizes.

.

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