Understanding Basic Statistics 6th Edition by Charles Henry Brase,Corrinne Pellillo Brase

Exercise 117

Supermarkets: Free Samples Do you take the free samples offered in supermarkets About 60% of all customers will take free samples. Furthermore, of those who take the free samples, about 37% will buy what they have sampled. (See reference in Problem 8.) Suppose you set up a counter in a supermarket offering free samples of a new product. The day you are offering free samples, 317 customers pass by your counter.
(a) What is the probability that more than 180 take your free sample
(b) What is the probability that fewer than 200 take your free sample
(c) What is the probabilty that a customer takes a free sample and buys the product Hint: Use the multiplication rule for dependent events. Notice that we are given the conditional probability P (buy | sample) = 0.37, while P (sample) = 0.60
(d) What is the probability that between 60 and 80 customers will take the free sample and buy the product Hint: Use the probability of success calculated in part (c).