Question

The reference desk of a university library receives requests for assistance. Assume that a Poisson probability distribution with an arrival rate of 10 requests per hour can be used to describe the arrival pattern and that service times follow an exponential probability distribution with a service rate of 12 requests per hour. What is the probability that no requests for assistance are in the system

Answer 1

0.1667

Explanation:

We are given;

Arrival rate, λ = 10 requests per hour

Service rate, μ = 12 requests per hour

From queuing theory, we know that;

ρ = λ/μ

Where ρ is the average proportion of time which the server is occupied.

Thus;

ρ = 10/12

ρ = 0.8333

Now, the probability that no requests for assistance are in the system is same as the probability that the system is idle.

This is given by the Formula;

1 - ρ

probability that no requests for assistance are in the system = 1 - 0.8333 = 0.1667