Question 1

If service times follow a negative exponential distribution, the probability of any very long service time is high.

Accepted Answer

A) True 
 B)False

Question 2

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

Accepted Answer

The answer of The ________ of a waiting line and...

Question 3

In queuing problems, the term renege refers to the fact that some customers leave the queue before service is completed.

Accepted Answer

A) True 
 B)False

Question 4

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

Accepted Answer

The costs are the cost of providing serv

Question 5

A waiting line meeting the assumptions of M/M/1 has an average time between arrivals of 15 minutes, and it services items in an average of 10 minutes each. What is the utilization factor?

Accepted Answer

A)  0.25 
B)  0.33 
C)  0.50 
D)  0.67 
E)  1.50 
A)  0.25 
B)  0.33 
C)  0.50 
D)  0.67 
E)  1.50

Question 6

A concert hall, employing both ticket takers and ushers to seat patrons, behaves typically as which of the following?

Accepted Answer

A)  multiple-server, single-phase system 
B)  multiple-server, multiphase system 
C)  single-server, single-phase system 
D)  single-server, multiphase system 
E)  multiple-server, cross-phase system 
A)  multiple-server, single-phase system 
B)  multiple-server, multiphase system 
C)  single-server, single-phase system 
D)  single-server, multiphase system 
E)  multiple-server, cross-phase system

Question 7

A(n) ________ queuing system is one in which the customer receives service from only one station and then exits the system.

Accepted Answer

The answer of A(n) ________ queuing system is one in...

Question 8

A waiting-line system has three parts: the size of the arrival population, the behavior of arrivals, and the statistical distribution of arrivals.

Accepted Answer

A) True 
 B)False

Question 9

A finite population waiting line model with N = 5 can serve 20 customers/day. There are 5 arrivals/day. What is the average number of customers in the queue?

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  .1 
E)  10 
A)  0 
B)  1 
C)  2 
D)  .1 
E)  10

Question 10

A single-phase waiting-line system meets the assumptions of constant service time or M/D/1. Units arrive at this system every 12 minutes on average. Service takes a constant 8 minutes. What is the average length of the queue, Lq, in units?

Accepted Answer

A)  0.67 
B)  2.5 
C)  4.5 
D)  5.0 
E)  7.5 
A)  0.67 
B)  2.5 
C)  4.5 
D)  5.0 
E)  7.5

Question 11

A waiting-line system that meets the assumptions of M/M/S has λ = 5, μ = 4, and M = 2. For these values, Po is approximately 0.23077, and Ls is approximately 2.05128. What is the average number of units waiting in the queue?

Accepted Answer

A)  approximately 0.1603 
B)  approximately 0.4103 
C)  approximately 0.8013 
D)  approximately 1.0417 
E)  Cannot be calculated because λ is larger than μ. 
A)  approximately 0.1603 
B)  approximately 0.4103 
C)  approximately 0.8013 
D)  approximately 1.0417 
E)  Cannot be calculated because λ is larger than μ.

Question 12

A queuing model that follows the M/M/1 assumptions has λ = 3 and μ = 2. What is the average number of units in the system?

Accepted Answer

A)  -3 
B)  3 
C)  0.667 
D)  150 percent 
E)  Growing without limit, since λ is larger than μ. 
A)  -3 
B)  3 
C)  0.667 
D)  150 percent 
E)  Growing without limit, since λ is larger than μ.

Question 13

A car wash is trying to determine how long the average line for a wash will be. The probability distributions that describe arrival and service times are unknown. If 10 cars arrive each hour and must wait 12 minutes in the line, how long will the line be, on average?

Accepted Answer

A)  120 cars 
B)  2 cars 
C)  1 car 
D)  0.83 cars 
E)  5 cars 
A)  120 cars 
B)  2 cars 
C)  1 car 
D)  0.83 cars 
E)  5 cars

Question 14

At the order fulfillment center of a major mail-order firm, customer orders, already packaged for shipment, arrive at the sorting machine to be sorted for loading onto the appropriate truck for the parcel's address. The arrival rate at the sorting machine is at the rate of 100 per hour following a Poisson distribution. The machine sorts at the constant rate of 125 per hour.
(a) What is the average number of packages waiting to be sorted?
(b) What is the average number of packages in the sorting system?
(c) How long must the average package wait until it gets sorted?
(d) What would Lq and Wq be if the service rate were exponential, not constant?

Accepted Answer

(a) L_q = 100² / [(2)(125)(125 - 100)] = 1.

Question 15

The sign at the bank that reads, "Wait here for the first available teller," suggests the use of a ________ waiting line system.

Accepted Answer

A)  dynamic-server, single-phase 
B)  random-server, single-phase 
C)  single-server, multiphase 
D)  multiple-server, single-phase 
E)  multiple-server, multiphase 
A)  dynamic-server, single-phase 
B)  random-server, single-phase 
C)  single-server, multiphase 
D)  multiple-server, single-phase 
E)  multiple-server, multiphase

Question 16

In the M/M/1 waiting line model with an arrival rate of 3 per hour and a service rate of 6 per hour, the utilization factor for the system is approximately 0.333.

Accepted Answer

A) True 
 B)False

Question 17

What does it mean to have a patient customer in a waiting line?

Accepted Answer

A patient customer is one who

Question 18

Which of the following is most likely to violate a FIFO queue?

Accepted Answer

A)  supermarket with no express lanes 
B)  car repair garage 
C)  emergency room 
D)  fast-food restaurant 
E)  All of these are equally likely to violate a FIFO queue. 
A)  supermarket with no express lanes 
B)  car repair garage 
C)  emergency room 
D)  fast-food restaurant 
E)  All of these are equally likely to violate a FIFO queue.

Question 19

A large discount store and supermarket has a hair styling salon on its premises. The salon has several operators. Salon customers can shop in other parts of the store until their name is called for salon service, at which time the customer will be served by the next available stylist. This scenario provides an example of which of the following?

Accepted Answer

A)  multiple-server, limited queue length 
B)  single-server, multiphase, limited queue length 
C)  multiple-server, unlimited queue length 
D)  multiple single-server systems, limited queue length 
E)  single-server, unlimited queue length 
A)  multiple-server, limited queue length 
B)  single-server, multiphase, limited queue length 
C)  multiple-server, unlimited queue length 
D)  multiple single-server systems, limited queue length 
E)  single-server, unlimited queue length

Question 20

Which of the following is a measure of queue performance?

Accepted Answer

A)  utilization factor for the system 
B)  average queue length 
C)  probability of a specific number of customers in the system 
D)  average waiting time in the line 
E)  all of these 
A)  utilization factor for the system 
B)  average queue length 
C)  probability of a specific number of customers in the system 
D)  average waiting time in the line 
E)  all of these

Exam 20: Waiting-Line Models

If service times follow a negative exponential distribution, the probability of any very long service time is high.

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

In queuing problems, the term renege refers to the fact that some customers leave the queue before service is completed.

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

A waiting line meeting the assumptions of M/M/1 has an average time between arrivals of 15 minutes, and it services items in an average of 10 minutes each. What is the utilization factor?

A concert hall, employing both ticket takers and ushers to seat patrons, behaves typically as which of the following?

A(n) ________ queuing system is one in which the customer receives service from only one station and then exits the system.

A waiting-line system has three parts: the size of the arrival population, the behavior of arrivals, and the statistical distribution of arrivals.

A finite population waiting line model with N = 5 can serve 20 customers/day. There are 5 arrivals/day. What is the average number of customers in the queue?

A single-phase waiting-line system meets the assumptions of constant service time or M/D/1. Units arrive at this system every 12 minutes on average. Service takes a constant 8 minutes. What is the average length of the queue, Lq, in units?

A waiting-line system that meets the assumptions of M/M/S has λ = 5, μ = 4, and M = 2. For these values, Po is approximately 0.23077, and Ls is approximately 2.05128. What is the average number of units waiting in the queue?

A queuing model that follows the M/M/1 assumptions has λ = 3 and μ = 2. What is the average number of units in the system?

A car wash is trying to determine how long the average line for a wash will be. The probability distributions that describe arrival and service times are unknown. If 10 cars arrive each hour and must wait 12 minutes in the line, how long will the line be, on average?

The sign at the bank that reads, "Wait here for the first available teller," suggests the use of a ________ waiting line system.

In the M/M/1 waiting line model with an arrival rate of 3 per hour and a service rate of 6 per hour, the utilization factor for the system is approximately 0.333.

What does it mean to have a patient customer in a waiting line?

Which of the following is most likely to violate a FIFO queue?

Which of the following is a measure of queue performance?

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A single-phase waiting-line system meets the assumptions of constant service time or M/D/1. Units arrive at this system every 12 minutes on average. Service takes a constant 8 minutes. What is the average length of the queue, L_q, in units?

A waiting-line system that meets the assumptions of M/M/S has λ = 5, μ = 4, and M = 2. For these values, P_o is approximately 0.23077, and L_s is approximately 2.05128. What is the average number of units waiting in the queue?