Basic Queueing - Automatic Output Previous Next
We next will show you the output screen when the Excel template for queueing simulation is applied to the Littletown bank problem. This routine runs for 10,000 arrivals, and normally takes a few seconds, but we have the output stored for you to see immediately.
The output screen uses notation that was introduced in Chapter 17 of your textbook for some steady-state expected values (statistical means) and probabilities in a queueing system. (This same notation is used in the Queueing Theory Excel templates.) To refresh your memory, this notation is
  1. = expected number of customers in the system,
  2. = expected number just in the queue,
  3. = expected waiting time in the system for each individual customer,
  4. = expected waiting time in the queue for each individual customer,
  5. = probability that exactly n customers are in the system.
For each of these quantities, the automatic routine uses the data gathered in the simulation run to compute both a point estimate (the best available estimate given by a single number) and a 95% confidence interval (an interval of possible values that will include the value being estimated 95% of the time).
As you view these measures of performance on the output screen, think about whether you would tolerate line lengths and waiting times this large if you were the manager of a bank.