State the null and alternative hypotheses in the following situations by defining the parameters used. Also, state any assumptions that you need to make to conduct the test:
(a) The Postal Service wishes to prove that the mean delivery time for packages is less than 5 days.
(b) A financial institution believes that it has an average loan processing time of less than 10 days.
(c) A marketing firm believes that the average contract for a customer exceeds $50,000.
(d) A Web-order company wishes to test if it has improved its efficiency of operations by reducing its average response time.
(e) A manufacturer of consumer durables believes that over 70% of its customers are satisfied with the product.