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?

Question

amistre64 · Answer

the bell curve is divided iinto whay ; 96% at the right ?

amistre64 · Answer

i got an a intyping....honest lol

amistre64 · Answer

http://www.easycalculation.com/statistics/standard-deviation.php might be useful

amistre64 · Answer

thats the reverse of what you wanted .... gotta learn to read :)

anonymous · Answer

lol so this wont help me ? thanks anyway:)

anonymous · Answer

We make the curve standard normal. 
$$(X-\mu)/(\sigma)$$

 (140-100)/17
that's a z score of 2.353.  The probability of being that or higher can be looked up in a standard normal table.

It is a probability of about .0094.  Multiply this by the population of 6.575E9 to get the number of geniuses.

I get 61,805,000 geniuses.