For the following independent random samples, use the z-test and the 0.01 level of significance in testing Ho:u1 = u2 versus H1:u1 = u2.
x1 = 33.5 s1 = 6.4 n1 = 31
x2 = 27.6 s2 = 2.7 n2 = 30
2. The manager's assistant, who created a new brochure, randomly selects 400 current customers, then randomly chooses 200 to receive the standard brochure that has been used in the past, with the other 200 receiving the promising new brochure that he has developed. Of those receiving the standard brochure, 35% call for more information about the counseling session, while 42% of those receiving the new brochure call for more information. Using the 0.10 level of significance, is it possible that the superior performance of the new brochure was just due to chance and that the new brochure might really be no better than the old one?
The solution provides step by step method for the calculation of Z test. Formula for the calculation and Interpretations of the results are also included.