# brain sizes: Einstein's and women's

Bob LeChevalier lojbab at lojban.org
Mon Aug 5 13:23:11 EST 2002

Joseph A Nagy Jr <pagan_prince at bigfire-hsv.org> wrote:
>John Knight wrote:
>> Gallup bases it's surveys on polls of 2,000 Americans, and they are accurate
>> to within plus or minus 2%, EXCEPT that they are now run by jews, and these
>> jews have an agenda, and that agenda is to overthrow the government of the
>> United States, which means that the built-in bias in the poll questions is a
>> bigger hindrance to getting at the truth than any large sampling error that
>> might possibly exist in their polling methodology.
>
>As for Gallup polls and their sample size, I hardly think 2K people is
>good enough for an error of only +/- 2%, so unless you got a link to

He's wrong (as usual), but not by too far for once.  Here is the
reference.

http://whyfiles.org/009poll/math_primer.html
>Sample size is dictated by how accurate you must be, or how large a
> margin of error you can tolerate.
>Jessica Utts, a statistics expert at University of California at
> Davis, says you can usually estimate the margin of error by finding
> the square root of the sample size (n), then dividing 1 by that
> number:
>
>What is the margin of error if we sample 1,600 people?
>
>The square root of 1,600 = 40, and 1/40 = .025, or 2.5%. Thus the
> margin of error is 2.5%.

So you would need 2500 for a 2% error assuming a normal distribution.
But of course most statistical data is not exactly according to a
normal distribution, something the nincompoop doesn't understand.
Furthermore, polling data can be affected by bias.  From the same
site:
http://whyfiles.org/009poll/math_primer2.html

>A legitimate political poll should come with some information to help
> you assess it: the number of people contacted, when the poll was
> conducted, and the margin of error. The margin is typically phrased
> as "accurate to plus or minus 3 percentage points," for a true range
> of uncertainty of 6 percent.
>
>That's All There Is To It?
>Sorry. We need to discuss some limitations. First of all, one time in
> 20, the results can be outside the margin of error. So if you read a
> lot of polls, some of them will be wrong. It's part of the
> statistical game of chance.
>
>More important, remember that the margin of error is only valid if the
> poll was *perfectly* designed and *perfectly* executed. That means no
> errors in writing the questionnaire. And it means making sure
> everybody was treated equally.

lojbab