Exam 20: Queuing Analysis

____ is the process of a customer evaluating the waiting line and server system and deciding not to join the queue.

Which of the following cannot be found by queuing formulas?

____ is the use of a criterion that allows new arrivals to displace members of the current queue and become the first to receive service.

A flower shop has one employee in the front of the store to sell flowers out of the cooler.On Saturdays customers arrive every six minutes, on average.The employee can serve a customer every five minutes, on average.The owner of the store feels that if there are more than four customers in the store at one time, additional customers may not come in because the wait appears too long. a.What is the chance of four or more customers being in the store at one time? b.What is the total time (in minutes) a customer spends in the store? c.What is the average number of customers in the store?

Queuing models

A local hamburger chain is considering adding a drive-through window.They estimate that during the dinner hour, customer arrival rate will average 18 per hour and follow a Poisson distribution.Service times during this same period are estimated to follow an exponential distribution with a mean of 24 customers per hour. a.Determine the probability that the service facility (drive-through window) is idle.b.Determine the probability of four vehicles in the system. c.Determine the average number of vehicles waiting for service. d.Determine the average number of vehicles in the system. e.Determine the average time a vehicle spends waiting for service. f.Determine the average time a vehicle spends in the system. g.Determine the probability that an arriving vehicle has to wait for service

A multiple-server queuing model has three servers with a mean service time of five customers per server per hour.It has been determined that arrivals will average 12 per hour.Arrivals follow a Poisson distribution and service times follow an exponential distribution. a.Calculate the probability that all three service channels are idle. b.Determine the probability of five customers in the system. c.Determine the average number of customers waiting for service. d.Determine the average number of customers in the system. e.Determine the average time a customer spends waiting for service. f.Determine the average time a customer spends in the system. g.Determine the probability an arriving customer will wait for service.

Discuss the five key assumptions for the basic, single-channel waiting line model.

Which of the following variables is ordinarily not an output of waiting line analysis?

The mean arrival rate is used to express demand; the mean service rate is used to express a system's capacity.

Which of the following is not a psychological strategy for dealing with a long wait-time?

With a restaurant as an example, discuss the psychological methods used to affect customers' perceptions of waiting (to be seated, to be served, etc.).

Arrival distributions for queuing models

A university bookstore opens a booth and buys back used books during final exam week.From 9 to 12 in the morning students arrive at the rate of 35 per hour on average.The bookstore employee can service an average of 40 students per hour. a.What is the average length of the line? b.What is the average time (in minutes) a student spends in the bookstore (system)? c.What is the chance that the bookstore employee will be idle?

In queuing models, what are "channels"?

Since most service times follow an exponential distribution, there is no need to collect data on actual service times.

The arrival rate in queuing formulas is expressed as:

When $\lambda$ = $\mu$ , the operating characteristics are not defined, which means that these times and numbers of items grow infinitely large.

Describe seven operating characteristics of a waiting line (no formulas).

Contrast wait cost with server cost.Which is harder to estimate?