It is desired to test the null hypothesis μ = 40 against the alternative hypothesis μ > 40 on the basis of a random sample from a population with standard deviation 4.
(a) If the probability of a Type I error is to be 0.03 and the probability of Type II error is to be 0.08 for μ = 39, find the required size of the sample.
(b) If a level 0.01 test is used, what is β(38), the probability of Type II error when μ = 38?