The mean drying time of a certain paint in a certain applicationis 12 minutes. A new additive will be tested to see if it reducesthe drying time. One hundred specimens will be painted, and thesample mean drying time will be computed. Let μ be the mean dryingtime for the new paint. Assume the population standard deviation ofdrying times is 2 minutes. Assume that, in fact, the true meandrying time of the new paint is 11.5 minutes.
a) What are the null and alternative hypotheses?
b) For what values of should Ho be rejected so that the power ofthe test is .85? What will the level then be?
c) How large of a sample is needed so that a 5% level test haspower .85?
