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

x̄1 = 524s1 = 129

x̄2 = 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.