Response to the following problem:
During its first hour of operation customers arrive at the Wednesday Afternoon Store according to a Poisson process with a mean rate of 40 per hour. It takes the cashier an average of 90 seconds to check out a customer.
a. Simulate the arrival of 15 customers and determine the average time these customers spend waiting in line.
b. Develop an Excel or Extend simulation for this problem and run it 10 times, each over a 60-minute interval. On the basis of these 10 simulation runs, determine a 95% confidence interval for the average time a customer must wait in line to begin service.