operates a drive-up teller window that allows customers to complete bank transactions without getting out of their cars. On weekday mornings, arrivals to the drive-up teller window occur at random, with a mean rate of 24 customers per hour or 0.4 customers per minute. Answer the followings: a. What is the mean or expected number of customers that will arrive in a five-minute period? b. Assume that the Poisson probability distribution can be used to describe the arrival process. Use the mean arrival rate in part (a) and compute the probabilities that exactly 0,1, 2 and 3 customers in a five-minute period. c. Delays are expected if more than 3 customers arrive during any five-minute period. What is the probabilities that delays will occur?