A car manufacturer claims that its vehicles average at least 25 miles per gallon, with a population standard deviation of σ=2. We take a sample of n=36 cars to test fuel efficiency, and with to performance a one-sided hypothesis test of the manufacturer's claim at a level of α=.05.
a. What is the critical value for the sample mean?
b. Suppose the answer to part a is 23.5 (it is not, but assume it is to do part b). If the true value of efficiency in the population is 22.75, what is the power of this hypothesis test?