The following observations are the lengths of time that driers
set for 20 min actually operated: 19.69, 19.06, 19.15, 17.80,
19.49, 21.38, 19.79, 20.11, 18.54, 19.12, 22. 61, 16.71, 21.61,
16.08, 24.47, 13.23, 24.06, 19.56, 23.97, 18.80. Using MTEST
(a) Test the hypothesis µ = 20 versus µ f 20 at level of
significance a = 0.05.
(b) Carry out tests as in part (a) of µ = 21 and µ = 22 versus
a two-sided alternative at level of significance a = 0.05.