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To: Rudder
Exactly one-half of the population of America has an IQ of 100 or less.

No. 100 is the average IQ, not the median IQ (the median defines the point at which half are above and half below). It's very unlikely that the average and the median IQ values are exactly the same--this is only true for a perfect normal distribution. It's probably roughly true, but it's certainly not exactly true.

Just a statistics nit (and common error).

88 posted on 12/05/2005 7:07:14 AM PST by NonZeroSum
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To: NonZeroSum
It's very unlikely that the average and the median IQ values are exactly the same--this is only true for a perfect normal distribution.

Your general point about medians and means is correct, but it's not true that the mean and median are the same only for a normal distribution. Trivial counterexample: if half the population had IQs of 99 and the other half had IQs of 101, the mean and the median would both be 100. You can think up more complex variants yourself.

93 posted on 12/05/2005 7:11:59 AM PST by TheGhostOfTomPaine
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To: NonZeroSum

I was taking the data from an old WAIS manual, which has the mean, mode and median the same. I think the test was designed--or re-normed--to produce such a standard normal curve. But, in actuality, the number I used was a guess based upon those old norms.


97 posted on 12/05/2005 7:17:44 AM PST by Rudder
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