In a particular retail clothing store, approximately 20% of potential customers who walk into the store make a purchase. In a random sample of 25 customers that walked into the store, a. What is the probability that exactly 9 of the customers make purchases? Round to 3 significant digits. b. What is the probability that at least 2 of the customers make purchases? Round to 3 significant digits. c. How many of the customers are expected to make purchases? Round to 3 significant digits. d. What is the standard deviation of the number of customers who make purchases? Round to 3 significant digits.