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 4,000 miles. Suppose we select a sample of 40 tires and use a simulator to determine the tread life. What is the standard error of the mean?

Answer 1

Solution :

Given that,

mean = = 60000

standard deviation = = 4000

n = 40

The sampling distribution of mean and standard error is ,

= 60000

= / n = 4000 / 40 = 632.4555