In a supermarket the weekly demand D is normally distributed. In a

sampe of size n = 15 we …nd D = 31 and sD = 19.
(a) H0 : � = 30 versus Ha : � > 30 (3 methods; � = 5%)
(b) H0 : � = 16 versus Ha : � > 16 (2 methods, � = 10%)