1. You and some friends have decided to test validity of an advertisement by a local pizza restaurant, which says it delivers to the dormitories faster than 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 data by ordering 10 pizzas from the local pizza restaurant and 10 pizzas from the national chain at different times. 

1	2	3	4	5	6	7	8	9	10
Local	16.8	18.1	11.7	14.1	15.6	21.8	16.7	13.9	17.5	20.8
NChain	22.0	19.5	15.2	17.0	18.7	19.5	15.6	16.5	20.8	24.0

1. At the 0.05 level of significance, is there evidence that mean delivery time for the local pizza restaurant is less than the mean delivery time for the national pizza chain?
2. Construct a 95 percent confidence interval for the difference between two means.