the question should be done on Excel

Q 2:

A government agency wants to test a refining companys claim that the mileage achieved with its unleaded gasoline (A) is at most equal to and probably less than that achieved with its leaded gasoline (B). Fifteen car models are chosen; a given driver drives each model twice over the identical route. At random, each driver is given brand A or brand B first, then drives with the other brand during the second trip. This procedure is designed to assure that neither brand of gasoline is favored or handicapped by all drivers being fresh or tired, respectively. Because the agency statistician knows nothing about the probability distribution of the population of milespergallon differences, a sign test at the 2.5 percent level of significance is chosen. Make the test, using the governments following Table data.

TABLE: Gasoline Experiment

	Miles per Gallon
Car Model	Unleaded Gas (A)	Leaded Gas (B)
1	22.1	23.7
2	15.7	16.1
3	18.2	19.0
4	19.0	19.0
5	25.7	24.2
6	19.2	22.0
7	11.9	12.1
8	28.0	30.2
9	35.0	37.8
10	27.0	30.0
11	19.7	19.0
12	16.3	15.1
13	21.2	23.4
14	22.2	20.7
15	27.8	28.1