If the underlying populations are normally distributed and both population variances are equal, the test statistic follows a: @ a) Student's tdistribution with n1 + n2 - 2 degrees of freedom. 0 b) standard normal distribution if both samples are large. O c) standard normal distribution with n1 + n2 - 2 degrees of freedom. 0 d) Student's tdistribution with n - 1 degrees of freedom. MSA (mean square due to factor) is an unbiased estimator of the common variance 0'2 if: G) a) H0 is true in reality. 0 b) the population means are different. 0 c) H0 is rejected. 0 d) the assumption of normality is met. In a multiple comparison of means procedure, if all pairwise comparisons contain zero, we can infer that: G) a) the procedure requires more samples to make any decision. 0 b) no mean pairs are significantly different. 0 c) every mean pair is significantly different. 0 d) the ANOVA F test will definitely reject H0