Exam 21: The Modi and Vam Methods of Solving Transportation Problems

A waiting-line system that meets the assumptions of M/M/1 has λ = 1, μ = 4. For this system, P_o is __________ and utilization is __________.

A waiting line meeting the M/M/1 assumptions has an arrival rate of 4 per hour and a service rate of 12 per hour. What is the probability that the waiting line is empty?

Which of the following is not a measure of a queue's performance?

Suppose that 1 customer arrives each minute in a Poisson distribution. Is it more likely that 2 customers or 0 customers will arrive each minute?

A dental clinic at which only one dentist works is open only two days a week. During those two days, the traffic is uniformly busy with patients arriving at the rate of three per hour. The doctor serves patients at the rate of one every 15 minutes. a. What is the probability that the clinic is empty (except for the dentist)? b. What percentage of the time is the dentist busy? c. What is the average number of patients in the waiting room? d. What is the average time a patient spends in the office (wait plus service)? e. What is the average time a patient waits for service?

The study of waiting lines calculates the cost of providing good service but does not value the cost of customers' waiting time.

Which of the following represents an unlimited queue?

In the basic queuing model (M/M/1), arrival rates are distributed by

In queuing problems, which of the following probability distributions is typically used to describe the time to perform the service?

A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of λ = 7.5 vehicles per day (approximately Poisson in nature). The mechanic crew can service an average of μ = 10 vehicles per day with a repair time distribution that approximates an exponential distribution. a. What is the utilization rate for this service system? b. What is the average time before the facility can return a breakdown to service? c. How much of that time is spent waiting for service? d. How many vehicles are likely to be in the system at any one time?

Which part of a waiting line has characteristics that involve statistical distribution?

Suppose that customer arrivals are governed by a Poisson distribution. If the average arrival rate is 60 customers each hour, how many times will 60 customers arrive during a one hour period for each time that only 40 customers arrive.

Which one of the following is not a characteristic of a Model A or M/M/1 system?

What costs are present in waiting line analysis? How do these costs vary with the level of service?

The __________ of a waiting line and the probability that the queue is empty add to one.