Data from two independent normal random samples are shown below:

Sample 1:

5.8 5.1 3.9 4.5 5.4 Sample 2:

4.4 6.1 5.2 5.7

Assume the population variances are identical but unknown. a. Test 1 < 2 using = 0.01 b. Construct a 90% confidence interval for the difference in the means.