The same test is given to two classes of students in statistics. The first class

(41 students) has a mean score of 75 with a sample variance of 100; the second class (21 students) has a mean score of 80 with a sample variance of 121. Did one class perform substantially better than the other? State the relevant hypotheses and the assumptions which you are making, and com¬

pute the p-value. Also, compute a 90 percent confidence interval for the difference in the means.