The administrator of a nursing home would like to do a time-and-motion study of staff time spend per day performing nonemergency tasks. prior to the introduction of some efficiency measures, the average number of person-hours per day spent on these task was 휇=16. the administrator wants to test whether the efficiency measures have reduced the value of 휇. how many days must be sampled to test the proposed hypothesis if she wants a test having 훼=0.05and the probability of type ii error of at most 0.1 when the actual values of 휇is 12 hours or less? assume 휎=7.64