A study was done to compare the performances of engine bearings made of different compound...

A study was done to compare the performances of engine bearings made of different compounds (McCool 1979). Ten bearings of each type were tested. The following table gives the times until failure (in units of millions of cycles):

a. Use normal theory to test the hypothesis that there is no difference between the two types of bearings.

b. Test the same hypothesis using a nonparametric method.

c. Which of the methods—that of part (a) or that of part (b)—do you think is better in this case?

d. Estimate π, the probability that a type I bearing will outlast a type II bearing.

e. Use the bootstrap to estimate the sampling distribution of and its standard error.

f. Use the bootstrap to find an approximate 90% confidence interval for π.