Calculates the probability that a customer arriving to a queueing system has to wait for service, as opposed to starting service immediately upon arrival.
QTPMMS_PrWait(Arrival Rate, Service Rate, Servers)
There is an option to use a finite Queue Capacity, where customers in excess of Queue Capacity are not admitted to the queue:
QTPMMS_PrWait(Arrival Rate, Service Rate, Servers, Queue Capacity)
If the Queue Capacity argument is omitted, it is assumed infinite.
When the Queue Capacity is finite, QTPMMS_PrWait is the probability that an arriving customer has to wait for service. The other possibilities are that the customer does not have to wait, or that the customer balks (does not enter the system).
The probability that an arriving customer has to wait for service, given that (s)he does not balk, can be calculated as
(QTPMMS_PrWait - QTPMMS_PrBalk)/(1 - QTPMMS_PrBalk)
When the queue capacity is infinite, no customers will balk.