the proportion of families buying milk from company a in a certain city is believed to be p=0.6. if a random sample of 10 families shows that 3 or less buy milk from company a, we shall reject null hypothesis that p=0.6 in a favour of the alternative p<0.6. evaluate a if p= 0.6 and beta for alternative p=0.3 and p=0.4 and power of test