An experimenter wants to conduct a hypothesis test on a claim that there was no difference between two population means. That is, H0: ?1 - ?2 = 0. The experimenter randomly selected 10 items from the first population and 10 items from the second population. The population variances are assumed to be known. Specifically, the variance of the first population is 25 and the variance of the second population is 36. If you were to conduct the test for the experimenter.
A. Case I - Use z statistic with known population variances
B. Case II - Use t statistic, assuming variances are unknown but equal
C. Case III -Use t statistic, assuming variances unknown and unequal
D. Case IV - Use paired t test