Discussion:
The listed values are waiting times (in minutes) of customers.
Bank A
(Single waiting line)
6.5, 6.6, 6.7, 6.8, 7.1, 7.3, 7.4, 7.7, 7.7, 7.7
Mean=7.15
Bank B
(Multiple waiting lines)
4.2, 5.4, 5.8, 6.2, 6.7, 7.7, 7.7, 8.5, 9.3, 10.0
Mean=7.15
Questions:
1) Bank A customer will receive service within how many minutes of the mean.
2) Bank B customer will receive service within how many minutes of the mean.
Explain in details(step by step) how the answers will be achieved for the above two questions.
Related to the above subject, it is said that many banks once required that customers wait in separate lines at each teller's window, but most have now changed to a single main waiting line. Why did they make that change? The mean waiting time didn't change, because the waiting-line configuration doesn't affect the efficiency of the tellers. They changed to the single line because customers prefer waiting times that are more consistent with less variation. Thus thousand of banks made a change that resulted in lower variation (and happier customers), even though the mean was not affected.