Two random samples were selected independently from populations having normal distributions. The following statistics were extracted from the samples:

x1 = 42.3 x2 = 32.4

a. If s1 = 3 and s2 = 2 and the sample sizes are n1 = 50 and n2 = 50, construct a 95% confidence interval for the difference between the two population means.

b. If s1 = s2, s1 = 3, and s2 = 2, and the sample sizes are n1 = 10 and n2 = 10, construct a 95% confidence interval for the difference between the two population means.

c. If s1  s2, s1 = 3, and s2 = 2, and the sample sizes are n1 = 10 and n2 = 10, construct a 95%

confidence interval for the difference between the two population means.