A car manufacturer claims that its vehicles average at least 30 miles per gallon

A car manufacturer claims that its vehicles average at least 30 miles per gallon., with apopulation variance of 4. We take a sample of 8 cars to test fuel efficiency, and wish to perform ahypothesis test on the car manufacturers claim at a level of α=.975.22.

The critical value for the sample mean X , below which we will reject the null hypothesis of 30miles per gallon, is

:a. 27.5

b. 28.6

c. 29.1

d. 29.5

e. 30.023.

Suppose the answer to #22 is 29 (it isn’t, but assume it is for the following). Also, suppose thetrue population mean for fuel efficiency is 27.5 miles per gallon. Then, the Power of thishypothesis test is:

a. .0170

b. .0523

c. .5423

d. .7801

e. .9830