As the branch manager of a bank, naturally, you want to make your customers happy. An important factor in enhancing your customer satisfaction is reduced waiting times. You are not happy with the current estimates of the waiting times in your branch. Having learned in your Operations Management class, you know how to approach to solve this problem. You first collected data on the arrival and the service process; and found that the average interarrival time for your customers is 10 mins with sample standard deviation of 4 mins. You also found that the average service time (request processing time for a customer) is 8 mins with sample standard deviation of 5 mins. Suppose you currently employ only one teller.