Question 1

A hospital emergency room always follows a first-in, first-served queue discipline in the interest of fairness.

Accepted Answer

A) True 
 B)False

Question 2

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 140 per hour following a Poisson distribution. The machine sorts at the constant rate of 150 per hour.
a. What is the utilization rate of the system?
b. What is the average number of packages waiting to be sorted?
c. What is the average number of packages in the sorting system?
d. How long must the average package wait until it gets sorted?

Accepted Answer

(a) The utilization rate is = 140/150 =

Question 3

Arrivals or inputs to a waiting-line system have characteristics that include

Accepted Answer

A)  population size 
B)  population behavior 
C)  population's statistical distribution 
D)  A and C 
E)  A, B, and C 
A)  population size 
B)  population behavior 
C)  population's statistical distribution 
D)  A and C 
E)  A, B, and C

Question 4

Four of the most widely used waiting line models-M/M/1 or A, M/M/S or B, M/D/1 or C, and Limited population or D-all share three characteristics: Poisson arrivals, FIFO discipline, and exponential service times.

Accepted Answer

A) True 
 B)False

Question 5

Which of the following is an example of a finite arrival population?

Accepted Answer

A)  copy machines in a copying shop that break down 
B)  students at a large university registering for classes 
C)  shoppers arriving at a supermarket 
D)  cars arriving at a suburban car wash 
E)  all of the above 
A)  copy machines in a copying shop that break down 
B)  students at a large university registering for classes 
C)  shoppers arriving at a supermarket 
D)  cars arriving at a suburban car wash 
E)  all of the above

Question 6

A finite population waiting line model with a single server has an average service time T of 200 minutes and an average time between service requirements U of 300 minutes. Calculate the service factor X. If the population consists of 5 elements, what are the average number waiting, the average number being serviced, and the average number running? Refer to Table D.8.

Accepted Answer

The service factor is X = T / (T + U) =

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

As the average service rate μ grows larger, the slope of the distribution of service time probabilities grows larger and larger, eventually becoming positive.

Accepted Answer

A) True 
 B)False

Question 9

A college registrar's office requires you to first visit with one of three advisors and then with one of two financial professionals. This system is best described as

Accepted Answer

A)  single channel, single phase system 
B)  single channel, multi-phase system 
C)  multi-channel, single phase system 
D)  multi-channel, multi-phase system 
E)  multi-channel, cross-phase system 
A)  single channel, single phase system 
B)  single channel, multi-phase system 
C)  multi-channel, single phase system 
D)  multi-channel, multi-phase system 
E)  multi-channel, cross-phase system

Question 10

Waiting-line models are useful to operations in such diverse settings as service systems, maintenance activities, and shop-floor control.

Accepted Answer

A) True 
 B)False

Question 11

A queuing model which follows the M/M/1 assumptions has λ = 2 and μ = 3. The average waiting time in the system is

Accepted Answer

A)  2/3 
B)  1 
C)  1.5 
D)  2 
E)  6 
A)  2/3 
B)  1 
C)  1.5 
D)  2 
E)  6

Question 12

A waiting-line system with one waiting line and three sequential processing stages is a multi-channel single-phase system.

Accepted Answer

A) True 
 B)False

Question 13

A waiting line or __________ is where items or people are in a line awaiting service; __________ is a body of knowledge about waiting lines.

Accepted Answer

queue, que

Question 14

The cost of waiting decreases as the service level increases.

Accepted Answer

A) True 
 B)False

Question 15

A dental clinic at which only one dentist works is open only two days a week. During those two days, the traffic arrivals follow a Poisson distribution 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 is the probability that there are one or more patients in the system?
c. What is the probability that there are four patients in the system?
d. What is the probability that there are four or more patients in the system?

Accepted Answer

(a) P_o = 1 - 3/4 = 0.25; (b) The probabil

Question 16

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 17

The shopper who says to himself, "I've waited too long in this line. I don't really need to buy this product today," and leaves the store is an illustration of which element of arrival behavior?

Accepted Answer

A)  random arrival 
B)  renege 
C)  random departure 
D)  balk 
E)  none of the above 
A)  random arrival 
B)  renege 
C)  random departure 
D)  balk 
E)  none of the above

Question 18

A finite population waiting line model has an average service time T of 200 minutes and an average time between service requirements U of 300 minutes; the service factor X is

Accepted Answer

A)  0.20 
B)  0.40 
C)  0.60 
D)  0.67 
E)  2.5 
A)  0.20 
B)  0.40 
C)  0.60 
D)  0.67 
E)  2.5

Question 19

Which of the following is not an assumption of the M/M/1 model?

Accepted Answer

A)  The first customers to arrive are the first customers served. 
B)  Each arrival comes independently of the arrival immediately before and after that arrival. 
C)  The population from which the arrivals come is very large or infinite in size. 
D)  Customers do not renege. 
E)  Service times occur according to a normal curve. 
A)  The first customers to arrive are the first customers served. 
B)  Each arrival comes independently of the arrival immediately before and after that arrival. 
C)  The population from which the arrivals come is very large or infinite in size. 
D)  Customers do not renege. 
E)  Service times occur according to a normal curve.

Question 20

Which of the following is most likely to be served in a last-in, first-served (LIFS) queue discipline?

Accepted Answer

A)  customers checking out at a grocery store 
B)  the in-basket on a manager's desk 
C)  patients entering a hospital emergency room 
D)  patrons waiting to be seated in a casual-dining restaurant 
E)  all of the above 
A)  customers checking out at a grocery store 
B)  the in-basket on a manager's desk 
C)  patients entering a hospital emergency room 
D)  patrons waiting to be seated in a casual-dining restaurant 
E)  all of the above

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

A hospital emergency room always follows a first-in, first-served queue discipline in the interest of fairness.

Arrivals or inputs to a waiting-line system have characteristics that include

Four of the most widely used waiting line models-M/M/1 or A, M/M/S or B, M/D/1 or C, and Limited population or D-all share three characteristics: Poisson arrivals, FIFO discipline, and exponential service times.

Which of the following is an example of a finite arrival population?

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

As the average service rate μ grows larger, the slope of the distribution of service time probabilities grows larger and larger, eventually becoming positive.

A college registrar's office requires you to first visit with one of three advisors and then with one of two financial professionals. This system is best described as

Waiting-line models are useful to operations in such diverse settings as service systems, maintenance activities, and shop-floor control.

A queuing model which follows the M/M/1 assumptions has λ = 2 and μ = 3. The average waiting time in the system is

A waiting-line system with one waiting line and three sequential processing stages is a multi-channel single-phase system.

A waiting line or __________ is where items or people are in a line awaiting service; __________ is a body of knowledge about waiting lines.

The cost of waiting decreases as the service level increases.

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

The shopper who says to himself, "I've waited too long in this line. I don't really need to buy this product today," and leaves the store is an illustration of which element of arrival behavior?

A finite population waiting line model has an average service time T of 200 minutes and an average time between service requirements U of 300 minutes; the service factor X is

Which of the following is not an assumption of the M/M/1 model?

Which of the following is most likely to be served in a last-in, first-served (LIFS) queue discipline?

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A waiting line or is where items or people are in a line awaiting service; is a body of knowledge about waiting lines.