North Andover, MA
|reply to karlmarx |
Actually an IQ number is an abstract concept where 100 was set to be the average. So EXACTLY 50% of the population SHOULD have double digit IQ's, otherwise 100 needs to be adjusted so that is true.
•Some people have an IQ of exactly 100. Take this hypothetical group of IQs of 10 people:
This group has a mean IQ of 100, but only 2/10 people have a two-digit IQ.
•Variation may not be consistent in both directions. Take this hypothetical group of IQs of 10 people:
This group has a mean IQ of 100, but three are above, six are exactly 100, and only one is below the mean(and only that one has a two-digit IQ).
Actually, measured (by some test standard) intelligence of large groups fits the Normal distribution. The results are scaled so that the mean is 100 and the standard deviation is 15. In order for even the range between 70 and 130 to have meaning, thousands of samples are required. In this real case, half the population have an IQ of 100 or less, by definition.
The wider extremes are more difficult to evaluate. For example, Marilyn vos Savant's purported IQ of 190 or thereabouts is six standard deviations above the mean. There aren't enough samples tested by any standard test to establish that value from the test population. I suspect her IQ was extrapolated by scaling MENSA test results from its members IQ distribution.
North Andover, MA
|reply to grafenberg |
With very large sample sets, I believe, a normal distribution is achieved. So if you're just talking about the people in the room with you, then I agree, but if you're talking about 300m people, then that doesn't apply.
Edit: didn't see that someone had already reply'd with basically this same idea.