a. The average price of automobiles sold by a dealership is $24500. The dealership own believes that the average price is higher. A sample of 400 cars sold showed that the average price per car is $25100. Define the null and alternative hypotheses.
b. A number of marathon runners are practicing for a 42.195 kilometers race. The practice distances is normally distributed with a population standard deviation of 5 kilometers. The coaches believe that the runners cover longer distances than 42.195 kilometers to be better prepared for the actual race. A sample of 25 runners practice records showed that the mean practice distance is 43 kilometers. Specify the alternative hypothesis.