Exam 18: A: Waiting-Line Analysis

The following questions refer to this data for a multiple server, priority service queuing model: -What is the average number of high priority items waiting in line for service?

A department has 5 machines that each run for an average of 8.4 hours (exponential)before service is required.Service time average is 1.6 hours (exponential). (i)While running,each machine can produce 120 pieces per hour.With one server,what is the average hourly output actually achieved? (ii)With 2 servers,what is the probability that a machine would be served immediately when it requires service? (iii)If machine downtime cost is $100 per hour per machine,and server time costs $30 per hour,how many servers would be optimal?

If operators cost $15 per hour in wages and fringe benefits and machine downtime costs $75 per hour in lost production,what is the optimal number of operators for this bank of machines?

Which of the following is not a disadvantage of a single line for a multiple server queuing system?

What is the average time that a customer would have to wait in line before being served?

By how much would the average time in the system increase if only two tellers were on duty?

If a manager increases server utilization (assuming no change in the customer arrival rate)what happens to the customer waiting time?

A system has one service facility that on an average can service 10 customers per hour.The customers arrive at a variable rate,which averages 6 per hour.In this circumstance,no waiting lines will form.

A multiple server system has customers arriving at an average rate of five per hour and an average service time of forty minutes.The minimum number of servers for this system to be underloaded is:

Compared to a single server system with exponential service time,a single server system with a constant service time causes a reduction of 50 percent in the average number waiting in line.

The following questions refer to this data for a multiple server, priority service queuing model: -What is average time in the system for a high priority item?

The reciprocal of the average rate of arrivals is the average interarrival time.

When the cost incurred by all customers is not the same,an appropriate queuing model is:

What is the probability that a machine will have to wait for service with two operators?

Total queuing system costs are always minimized at the point where the costs of customers waiting are equal to the service capacity costs.

Infinite-source queuing models assume average arrival and service rates are stable.

The following questions refer to this data for a multiple server, priority service queuing model: -What is average time in line for a high priority item?

The cost of having customers wait has to be balanced with the cost of providing service capacity.

As the ratio of arrival rate to service rate is increased,which of the following is likely?

The following questions refer to this data for a multiple server, priority service queuing model: -What is the overall average arrival rate?