Question

The tread life of tires mounted on light-duty trucks follows the normal probability distribution with a population mean of 60,000 miles and a population standard deviation of 14,000 miles. Suppose we select a sample of 140 tires and use a simulator to determine the tread life. What is the standard error of the mean

Answer 1

`S.E=1183.2`

Explanation:

From the question we are told that:

Population mean
`\mu=60000`

Population standard deviation
`\sigma= 14,000 miles.`

Sample size
`n=140`

Generally the equation for Standard error is mathematically given by

`S.E=( \sigma)/( \sqrt n)`

`S.E= (14000)/(\sqrt 140)`

`S.E=1183`