Question

Costco installs automobile tires on a first-come first-serve basis. the total time a customer needs to wait for the installation to be completed follows the normal distribution with a mean time of 106.3 minutes and a standard deviation of 18.5 minutes. the interval around the mean that contains 68% of the wait time for customers is ________.

Answer 1

The interval would be from 87.8 to 124.8.

68% of the data fall within one standard deviation of the mean, so we calculate

106.3 +/- 18.5:

106.3 - 18.5 = 87.8
106.3 + 18.5 = 124.8