## anonymous 5 years ago 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 17, and if the population of the world is 6,575,000,000, how many geniuses are there in the world today?

1. Owlfred

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2. anonymous

$Z=\frac{140-100}{17}\approx2.35$$\Phi(2.35)=0.9906$So the proportion of people that would be classed as genius is: $1-0.9906=0.0094$So the amount of genuises is:$0.0094\times6.575\times10^9=61,805,000$