An auto maker estimates that the mean gas mileage of its sport utility vehicle is 20 miles per gallon. A random sample of 8 such vehicles had a mean of 18 per gallon and a standard deviation of 5 miles per gallon. At α=0.05, can you reject the auto maker's claim that the mean gas mileage of its sports utility vehicle is 20 miles per gallon? Assume the population is normally distributed.