Waiting time at a bank drive-in widow the average waiting time at a drive-in window of local bank is 10.3 minutes, with a standard deviation of 2.7 minutes. Assumes the variable is normally distributes. If a customer arrives at the bank, find the probability that the customer will have to wait a. between 4 and 9 minutes. B. less than 5 minutes or more than 10 minutes. C. how might a customer estimate his or her approximate waiting time?