9.22

1. The 90% confidence interval is (0.04611, 0.09674).
2. The 95% confidence interval is (0.04126, 0.10156).
3. The answer is (b) the 95% confidence interval.

The answer is (d).

10.6

a) H0: u = 32 versus H1: u>32.

b) We obtain a test statistic value of z = 8.27 and a p-value of nearly 0. so we would reject H0.

10.10

H0: u = 70 versus H1: u>70.

Test we have : t=2.509, Using the t-distribution table, the p-value would be reported as : 0.01<p-value<0.05.
Reject Ho.
 

10.16

a) Test we have : t=-8.8, p-value is nearly 0. Using the t-distribution table we have that p-value is

much less than 0.005(nearly 0)