Question

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. If a certain statistician has an of 122 , what percent of the population has a lower IQ?

A. 47%
B. 93%
C. 22%
D. 99%
E. 7%

Answer 1

B. 93%

Explanation:

Find the z-score:

z = (x − μ) / σ

z = (122 − 100) / 15

z = 1.47

Find the probability using a calculator or z-score table.

P(Z < 1.47) = 0.93