Assume that IQ scores are normally distributed, with a mean $mu$ of 100 and standard deviation $sigma$ of 15. What is the probability that a randomly selected person has an IQ score greater than 120?

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Answer 1 · 2015-02-18T15:25:14

$0.0912 or 9.12%$

I did this on a TI-83 plus:

(2nd)-Distr
Choose normalcdf from the menu

Fill in:

$(120,10^99,100,15)$ and Enter

$120=$ lower bound,
$10^99=$ upper bound,
$100=$ mean $mu$
$15=$ standard deviation $sigma$

Assume that IQ scores are normally distributed, with a mean mumu of 100 and standard deviation sigmasigma of 15. What is the probability that a randomly selected person has an IQ score greater than 120?