SOLUTION: On a particular test, IQ scores for adults follow a bell-shaped (symmetric) distribution with mean=100 and a standard deviation of 15. In a random sample of 300 adults, approximate

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Question 414025: On a particular test, IQ scores for adults follow a bell-shaped (symmetric) distribution with mean=100 and a standard deviation of 15. In a random sample of 300 adults, approximately how many would have IQs of at least 85?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

*Note: z+=+blue%28x+-+mu%29%2Fblue%28sigma%29

   z = 85-100/15 = -15/15 = -1

P ( z ≥ -1) = 1 - .1587 = .8413  OR 84.13%

  300*.8413 ~ 252 adults would have IQs of at least 85