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6) Customers arrive at a bank according to a Poisson process with rate 8 per hour. Calculate: a) Mean and stande deviation of the number of customers who enter the bank during a 8-hour long workday, from 9:00AM to 5:00PM b) Probability that more than four customers enter the bank during a lunch break period of one houn c) Probability that during the last 15 minutes of the workday no customers arrive; d) Probability that not more than 2 customers arrive between 3:00PM and 3:30PM, given that E2 customers arrive between 3 :00 and 5:00PM