Some psychologists believe that a "genius" should be defined as anyone having an IQ over 140. If IQ scores are normally distributed with a mean of 100 and a standard deviation of 13, and if the population of the world is 6,575,000,000, how many geniuses are there in the world today?

Question

anonymous · Answer

i forgot the percentages but it's a little over 3 standard deviations to the right...

directrix · Answer

The z score is (140 - 100) / 13 = 3.07.

As best I can read the chart, the associated area to the right of 3.07 is .0011.

6,575,000,000 * .0011 = 7, 232, 500 "geniuses."

Do check my work.

anonymous · Answer

i wonder how many of that are in here at OS?