Question

A random sample of 36 trucks traveling on a section of an interstate showed an average speed of 71 mph. The distribution of speeds of all trucks on this section of highway is normally distributed with a standard deviation of 10.5 mph. The value to use for the standard error of the mean is:

Answer 1

Answer: 1.75

Explanation:

The formula to find the standard error is given by :-

`S.E.=(\sigma)/(√(n))`

Given : The sample size : n = 36

The distribution of speeds of all trucks on this section of highway is normally distributed with standard deviation :
`\sigma=10.5\text{ mph}`

Then , the standard error of the mean will be :-

`S.E.=(10.5)/(√(36))=1.75`

Hence, the value to use for the standard error of the mean is : 1.75