Assume that you have a sample of n,8, with the sample mean R, 42, and a sample standard deviation of S, 4, and you have an independent sample of hy 15 tom another population with a sample mean of R, 34 and a sample standard deviation of 5, 5. What assumptions about the two populations are necessary in order to perform the pooled-variance t test for the hypothesis Hy sy against the atemative Hy ay Pag and make a statistical decision? Choose the correct answer below A. necessary to assume that the populations from which you are sampling have negative Igrar test statistics and unequal sample means B. necessary to assume that the populations from which you are sampling have equal population means and positive standard deviations C. ct is necessary to assume that the populations from which you are sampling have unequal variances and equat sis D. necessary to assume that the populations from which you are sampling have independent normal distributions and equal variances