A small coffee shop has a single barista. Because the shop is small, there are no tables or chairs. Consequently, customers wait in a single line to order and receive their coffee and leave the shop as soon as their order is received. Customers arrive at the shop at the rate of 15 per hour. It is estimated that the barista needs, on average, 120 seconds (exponentially distributed) to serve each customer. Determine the following service operating characteristics for the coffee shop:
a. Average server utilization
b. Average line length in the coffee shop
c. Average time spent in line
d. Average number of customers in the coffee shop
e. Average time spent by customers in the coffee shop (includes waiting time and service time)