13.5 In random samples of 25 from each of two normal populations, we found the following statistics ...

13.5 In random samples of 25 from each of two normal populations, we found the following statistics:
x-bar1 = 524 s1 = 129
x-bar2 = 469 s2 = 141
a. Estimate the difference between the two population means with 95% confidence. b. Repeat part (a) increasing the standard deviations to s1 = 255 and s2 = 260. c. Describe what happens when the sample standard deviations get larger. d. Repeat part (a) with samples of size 100. e. Discuss the effects of increasing the sample size.