You and some friends have decided to test the validity of an advertisement by a local pizza restaurant,

You and some friends have decided to test the validity of an advertisement by a local pizza restaurant, which says it delivers to the dormitories faster than a local branch of a national chain. Both the local pizza restaurant and national chain are located across the street from your college campus. You define the variable of interest as the delivery time, in minutes, from the time the pizza is ordered to when it is delivered. You collect the data by ordering 10 pizzas from the local pizza restaurant and 10 pizzas from the national chain at different times. You organize and store the data in . Table 10.2 shows the delivery times. PizzaTime EXAMPLE 10.1 Testing for the Difference in the Mean Delivery Times 370 CHAPTER 10 Two-Sample Tests TABLE 10.2 Delivery Times (in minutes) for Local Pizza Restaurant and National Pizza Chain Local Chain 16.8 18.1 22.0 19.5 11.7 14.1 15.2 17.0 15.6 21.8 18.7 19.5 16.7 13.9 15.6 16.5 17.5 20.8 20.8 24.0 At the 0.05 level of significance, is there evidence that the mean delivery time for the local pizza restaurant is less than the mean delivery time for the national pizza chain?