An experiment was initiated to study the effect of a newly developed gaso- line detergent on automobile mileage. The following data, representing mileage per gallon before and after the detergent was added for each of eight cars, resulted.
|
Car
|
Mileage without Additive
|
Mileage with Additive
|
|
1
|
24.2
|
23.5
|
|
2
|
30.4
|
29.6
|
|
3
|
32.7
|
32.3
|
|
4
|
19.8
|
17.6
|
|
5
|
25.0
|
25.3
|
|
6
|
24.9
|
25.4
|
|
7
|
22.2
|
20.6
|
|
8
|
21.5
|
20.7
|
Find the p-value of the test of the hypothesis that mileage is not affected by the additive when
• the sign test is used;
• the signed rank test is used.