Returns the probability that a customer waits less than or equal to Threshold Time time units. (This function is the cumulative distribution function for the waiting time).
For example, if Threshold Time is 2 minutes and this function returns 0.80 it means that 80% of customers wait 2 minutes or less. Note that the Threshold Time must be entered using the same time units as the Arrival Rate and Service Rate. If these rates are per hour then a Threshold Time of 2 minutes should be entered as: (2 minutes)(1 hour / 60 minutes) = 1/30 hours
QTPMMS_ServiceLevel(Threshold_Time, 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_ServiceLevel(Threshold_Time, 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_ServiceLevel is the probability that an arriving customer has to wait Threshold Time or less for service. The other possibilities are that the customer has wait longer than Threshold Time, or that the customer balks (does not enter the system).
The probability that an arriving customer has to wait Threshold Time or less for service, given that (s)he does not balk, can be calculated as
(QTPMMS_ServiceLevel - QTPMMS_PrBalk)/(1 - QTPMMS_PrBalk)
When the queue capacity is infinite, no customers will balk.