4. A manufacturer can use either the postal services or private shipper to deliver its small shipments. To help in making a choice, the manufacturer selects 10 destination and ships parcels to each destination by each carrier. The delivery times (in days) are: Destination 1 2 3 4 5 6 7 8 9 10 Postal 3 4 5 4 8 9 7 10 9 9 Private 2 2 3 5 4 6 9 6 7 6 a) m Provide the relevant Minitab output and explain how you use it to check if the normality assumption(s) needed for part b) is(are) met. b) Suppose the manufacture consults you for help in making the choice. Calculate and interpret an appropriate 95% condence interval. Explain your recommendation