Independent random samples from normal populations produced the results shown here.

Sample 1 Sample 2 3.1 2.7 1.7 3.6 2.8 3.9 3.0

a. Calculate the pooled estimate of a2.

b. Do the data provide suffic~ent evidence to indicate that p, > p,? Test using a = .lo.

c. Find a 90% confidence interval for (p, - pZ).

d. Which of the two inferential procedures, the test ot h!-

pothesis in part b or the confidence interval in part c, provides more information about (p, - p,)?