Which of the following are true statements about hypothesis

Which of the following are true statements about hypothesis tests to compare two population means? Do is the amount by which the population means are hypothesized to differ. Although this amount if often 0 (if the means are hypothesized to be equal), it does not have to be zero. The z-distribution is used to obtain the critical value for the rejection region and decision rule whenever at least one of the sample sizes is sufficiently large (either n1 or n2 is at least 30). Both A and B. Neither A or B.

Solution

Only B is true. For U1-U2 = 0 , it has to be equal everytime hence option A is False