:

Car 1 Car 2 Car 3 Car 4 Car 5 Car 6

Brand A 125 64 100 38 96 112

Brand B 131 65 103 37 102 115

(For instance, after Car 1 was outfitted with 4 new brand A tires and then driven for one month, the total wear on the 4 tires was 125/1000th of an inch; after it was driven for one month with new brand B tires, the total wear on the 4 tires was 131/1000th of an inch.) Let the null hypothesis be that tires of brand A and tires of brand B wear about equally, and the alternative hypothesis be that tires of brand B are longer-wearing. Assume that the six differences in tire wear (like 131 - 125 = 6 and 37 -38 = -1) are a random sample from a large collection of such differences whose histogram follows the normal curve. If you test the null hypothesis against the alternative, the P-value should turn out to be

a. less than or equal to .05%

b. bigger than .05%, but less than or equal to 2.5%

c. bigger than 2.5%, but less than or equal to 5%

d. bigger than 5%, but less than or equal to 10%

e. bigger than 10%