On Thu, Feb 03, 2005 at 12:38:55PM -0700, Howard Brazee wrote: > George Carlin's statement is misleading. The average IQ is a range. > It is closer to being correct to say 1/2 of the population is average, > leaving 1/4 above and 1/4 below average. (I don't know what the actual > numbers are - nor even whether standard deviation means much here). > Average people get treated one way in school, and the extremes get treated > other ways. It's been a while so I don't have the exact number at my fingertips, but here's the scoop. Obligatory disclaimer: IQ test is a mediocre measure of intelligence at best. I neither endorse nor disclaim it. The following merely discusses IQ as a descriptive statistic. IQ tests are normalized (ie, multipliers and other adjusters applied) so the average is 100 and the standard deviation is 10. Plot the IQs of a population as a graph, and you get a standard bell curve. In a standard bell curve, approx 68% (I think) of the values are within 1 standard deviation of the mean. Applied to a population, that'd mean 68% are from 90 to 110 IQ. Of the remaining 32%, half are below 90, half above 110. There's nothing saying that being within one standard deviation of the mean is 'normal' with respect to intelligence. But Carlin is almost correct when he says that half the population is below average (100). What he's missing is the small but real number of folks who are actually exactly on the average. At least when I was in school, you pretty much had to be at least two standard deviations from the norm to be extreme. Beyond three deviations the IQ test ceases to have much qualitative meaning except 'extreme.' Steve "why yes, I do know my IQ" Simmons -- "In my darker moments I consider creating the eeyore fan club with a theme song by Leonard Cohen, logo by Edvard Munch and costumes by Tim Burton." -- anonymous, forwarded by Ellen.