(Bank Branch) One teller has been serving all customers at a local bank branch in a small town of Boston. Customers arrive in a mean of 1/15 hours (or 4 minutes) with a standard deviation of 1/15 hours. The teller spends a mean of 1/20 hours (or 3 minutes) with a standard deviation of 1/20 hours. Customers visit the branch for different tasks, which creates the variability of service times. Some of their requests, such as money withdrawals, take a short time whereas others such as foreign money deposits take long. 11. (Bank Branch) The queue is __. (Hint: Calculate utilization.) A. stable B. not stable 12. (Bank Branch) --- Use the posted queueing template to find average flow time (W). Use the Little's law to find average customers in the entire system (L). (Hint: L includes customers in the waiting line and those in service.) A. 0.2, 3 E. 0.3,3 B. 0.2,4 F. 0.3,4 C. 0.26,3 G. 0.36,3 D. 0.26,4 H. 0.36,4 13. (Bank Branch) - Use the average flow time (W) to find the average waiting time (W). (Hint: average flow time (W) = average waiting time (W) + mean service time (t)) - Use the Little's law to find average customers in the waiting line (La). (Hint: La includes customers in the waiting line, but not those in service.) A. 0.15, 1.25 E. 0.35, 1.25 B. 0.15, 2.25 F. 0.35, 2.25 C. 0.25, 1.25 G. 0.45, 1.25 D. 0.25, 2.25 H. 0.45, 2.25 14. (Bank Branch) As a part of job enrichment program, the bank teller left the branch for a week and was replaced by his manager. Unfortunately, the branch manager is not familiar with the teller's job and his mean service time (t) is twice the teller's mean service time. The queue is (Hint: Recalculate utilization with manager's mean service time.) During the next week, average flow time (W) A. stable, remains the same B. not stable, remains the same C. stable, grows D. not stable, grows (Bank Branch) One teller has been serving all customers at a local bank branch in a small town of Boston. Customers arrive in a mean of 1/15 hours (or 4 minutes) with a standard deviation of 1/15 hours. The teller spends a mean of 1/20 hours (or 3 minutes) with a standard deviation of 1/20 hours. Customers visit the branch for different tasks, which creates the variability of service times. Some of their requests, such as money withdrawals, take a short time whereas others such as foreign money deposits take long. 11. (Bank Branch) The queue is __. (Hint: Calculate utilization.) A. stable B. not stable 12. (Bank Branch) --- Use the posted queueing template to find average flow time (W). Use the Little's law to find average customers in the entire system (L). (Hint: L includes customers in the waiting line and those in service.) A. 0.2, 3 E. 0.3,3 B. 0.2,4 F. 0.3,4 C. 0.26,3 G. 0.36,3 D. 0.26,4 H. 0.36,4 13. (Bank Branch) - Use the average flow time (W) to find the average waiting time (W). (Hint: average flow time (W) = average waiting time (W) + mean service time (t)) - Use the Little's law to find average customers in the waiting line (La). (Hint: La includes customers in the waiting line, but not those in service.) A. 0.15, 1.25 E. 0.35, 1.25 B. 0.15, 2.25 F. 0.35, 2.25 C. 0.25, 1.25 G. 0.45, 1.25 D. 0.25, 2.25 H. 0.45, 2.25 14. (Bank Branch) As a part of job enrichment program, the bank teller left the branch for a week and was replaced by his manager. Unfortunately, the branch manager is not familiar with the teller's job and his mean service time (t) is twice the teller's mean service time. The queue is (Hint: Recalculate utilization with manager's mean service time.) During the next week, average flow time (W) A. stable, remains the same B. not stable, remains the same C. stable, grows D. not stable, grows