Exhibit 8-3
A random sample of 81 automobiles traveling on a section of an interstate showed an average speed of 60 mph. The distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 13.5 mph.
-Refer to Exhibit 8-3. The value to use for the standard error of the mean is
A)13.5
B)9
C)2.26
D)1.5

Question

Quizplus · Accepted Answer

The standard error of the mean is calculated as the standard deviation divided by the square root of the sample size: 13.5 / √81 = 1.5.

Exhibit 8-3 A Random Sample of 81 Automobiles Traveling on a Section