22 Refer to Exercise 21. Conduct a two-sample t -test of the null hypothesis that the two treatment means are equal for each dot plot. Use a = .05 and two-tailed tests. In the course of the test, compare each of the following with the F -tests in Exercise 21:

a. The pooled variances and the MSEs

b. The t - and the F -test statistics

c. The tabled values of t and F that determine the rejection regions

d. The conclusions of the t - and F -tests

e. The assumptions that must be made in order to ensure the validity of the t - and F -tests