3. Arrivals are independent of preceding arrivals, but the average number of arrivals (the arrival rate) does not change over time.
4. Arrivals are described by a Poisson probability distribution and come from an infinite or very large population.
5. Service time also vary from one passenger to the next and are independent of one another, but their average rate is known.
6. Both the number of items in queue at anytime and the waiting line experienced by a particular item are random variables.
7. Service times occur according to the negative exponential probability distribution.
8. Thee average service rate is greater than the average arrival rate.
9. The waiting space available for customers in the queue is infinite.