Question

In the U.S, the IQ test has a normal distribution with a mean of 100 and a standard deviation of 15. What percent of the population has an IQ more than 133?

Answer 1

1.32%

Explanation:

First, find the z-score:

z = (x − μ) / σ

z = (133 − 100) / 15

z = 2.2

Use a calculator or z-score table to find the probability.

P(x > 2.2) = 1 − 0.9868

P(x > 2.2) = 0.0132

1.32% of the population has an IQ more than 133.