Question 1

The source population is considered to be either ________ in its size.

Accepted Answer

A)  finite or infinite 
B)  fixed or variable 
C)  known or unknown 
D)  random or scheduled 
E)  small or large 
A)  finite or infinite 
B)  fixed or variable 
C)  known or unknown 
D)  random or scheduled 
E)  small or large

Question 2

Which one of the following is NOT a characteristic of a Model B or M/M/S system?

Accepted Answer

A)  unlimited population size 
B)  single server 
C)  exponential service time pattern 
D)  single phase 
E)  Poisson arrival rate pattern 
A)  unlimited population size 
B)  single server 
C)  exponential service time pattern 
D)  single phase 
E)  Poisson arrival rate pattern

Question 3

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 time a unit spends in this system?

Accepted Answer

A)  approximately 0.1603 
B)  approximately 0.2083 
C)  approximately 0.4103 
D)  approximately 0.8013 
E)  Cannot be calculated because λ is larger than μ. 
A)  approximately 0.1603 
B)  approximately 0.2083 
C)  approximately 0.4103 
D)  approximately 0.8013 
E)  Cannot be calculated because λ is larger than μ.

Question 4

A(n) ________ queuing system has one line and one server.

Accepted Answer

The answer of A(n) ________ queuing system has one line...

Question 5

A finite population waiting line model (D) differs from the single service model (A) in that:

Accepted Answer

A)  it has more than one server. 
B)  the average length of the queue is less than 5. 
C)  customers are served first-come, first-served. 
D)  arrivals are Poisson distributed. 
E)  the population of people or units seeking service is finite. 
A)  it has more than one server. 
B)  the average length of the queue is less than 5. 
C)  customers are served first-come, first-served. 
D)  arrivals are Poisson distributed. 
E)  the population of people or units seeking service is finite.

Question 6

You have seen that, in an M/D/1 problem, the average queue length is exactly one-half the average queue length of an otherwise identical M/M/1 problem. Are all other performance statistics one-half as large also? Explain.

Accepted Answer

Only the average queue length

Question 7

The two characteristics of the waiting line itself are whether its length is limited or unlimited and the discipline of the people or items in it.

Accepted Answer

A) True 
 B)False

Question 8

Which of the following is a requirement for application of Little's Law to be valid?

Accepted Answer

A)  arrival rates that follow the Poisson distribution 
B)  FIFO queue discipline 
C)  steady state conditions 
D)  single-server system 
E)  multiphase system 
A)  arrival rates that follow the Poisson distribution 
B)  FIFO queue discipline 
C)  steady state conditions 
D)  single-server system 
E)  multiphase system

Question 9

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 probability distribution. 
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 probability distribution.

Question 10

Identify the seven major measures of a queue system's performance.

Accepted Answer

• The average time each customer or obje

Question 11

Of the three types of queue discipline, only ________ is assumed by the four primary waiting line models.

Accepted Answer

FIFO or FIFS or firs

Question 12

A queuing model that follows the M/M/1 assumptions has λ = 2 and μ = 5. What is the average number of units in the system?

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 13

Suppose that, on average, 4 customers arrive each minute in a Poisson distribution. What is the probability that 2 customers will arrive in a particular minute?

Accepted Answer

A)  0.500 
B)  0.147 
C)  0.018 
D)  0.073 
E)  0.195 
A)  0.500 
B)  0.147 
C)  0.018 
D)  0.073 
E)  0.195

Question 14

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 which of the following?

Accepted Answer

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

Question 15

A waiting-line system that meets the assumptions of M/M/1 has λ = 2, μ = 5. Calculate P0. Build a table showing the probability of more than 0, 1, 2, 3, 4, 5, 6, and 7 units in the system. Round to six decimal places in your work

Accepted Answer

Question 16

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

Accepted Answer

A)  arrivals or inputs 
B)  the waiting line itself 
C)  the service facility 
D)  A and C 
E)  A, B, and C 
A)  arrivals or inputs 
B)  the waiting line itself 
C)  the service facility 
D)  A and C 
E)  A, B, and C

Question 17

A waiting line meeting the M/M/1 assumptions has an arrival rate of 8 per hour and a service rate of 12 per hour. What is the probability that the waiting line is empty?

Accepted Answer

P_o = 1 - λ/

Question 18

Which of the following represents an unlimited queue?

Accepted Answer

A)  drive-through lane at a fast-food restaurant 
B)  small barbershop with only 5 chairs for waiting customers 
C)  toll booth serving automobiles on an interstate 
D)  faculty office with limited seating during office hours 
E)  restaurant with no outside seating and limited capacity due to fire department restrictions 
A)  drive-through lane at a fast-food restaurant 
B)  small barbershop with only 5 chairs for waiting customers 
C)  toll booth serving automobiles on an interstate 
D)  faculty office with limited seating during office hours 
E)  restaurant with no outside seating and limited capacity due to fire department restrictions

Question 19

Students arrive randomly at the help desk of the computer lab. There is only one service agent, and the time required for inquiry varies from student to student. Arrival rates have been found to follow the Poisson distribution, and the service times follow the negative exponential distribution. The average arrival rate is 12 students per hour, and the average service rate is 20 students per hour. How many students, on average, will be waiting in line at any one time?

Accepted Answer

A)  0.9 students 
B)  1.5 students 
C)  3 students 
D)  4 students 
E)  36 students 
A)  0.9 students 
B)  1.5 students 
C)  3 students 
D)  4 students 
E)  36 students

Question 20

Students arrive randomly at the help desk of the computer lab. There is only one service agent, and the time required for inquiry varies from student to student. Arrival rates have been found to follow the Poisson distribution, and the service times follow the negative exponential distribution. The average arrival rate is 12 students per hour, and the average service rate is 20 students per hour. On average, how long does it take to service each student?

Accepted Answer

A)  1 minute 
B)  2 minutes 
C)  3 minutes 
D)  5 minutes 
E)  20 minutes 
A)  1 minute 
B)  2 minutes 
C)  3 minutes 
D)  5 minutes 
E)  20 minutes

Exam 20: Waiting-Line Models

The source population is considered to be either ________ in its size.

Which one of the following is NOT a characteristic of a Model B or M/M/S system?

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 time a unit spends in this system?

A(n) ________ queuing system has one line and one server.

A finite population waiting line model (D) differs from the single service model (A) in that:

You have seen that, in an M/D/1 problem, the average queue length is exactly one-half the average queue length of an otherwise identical M/M/1 problem. Are all other performance statistics one-half as large also? Explain.

The two characteristics of the waiting line itself are whether its length is limited or unlimited and the discipline of the people or items in it.

Which of the following is a requirement for application of Little's Law to be valid?

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

Identify the seven major measures of a queue system's performance.

Of the three types of queue discipline, only ________ is assumed by the four primary waiting line models.

A queuing model that follows the M/M/1 assumptions has λ = 2 and μ = 5. What is the average number of units in the system?

Suppose that, on average, 4 customers arrive each minute in a Poisson distribution. What is the probability that 2 customers will arrive in a particular minute?

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 which of the following?

A waiting-line system that meets the assumptions of M/M/1 has λ = 2, μ = 5. Calculate P0. Build a table showing the probability of more than 0, 1, 2, 3, 4, 5, 6, and 7 units in the system. Round to six decimal places in your work

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

A waiting line meeting the M/M/1 assumptions has an arrival rate of 8 per hour and a service rate of 12 per hour. What is the probability that the waiting line is empty?

Which of the following represents an unlimited queue?

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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 time a unit spends in this system?

A waiting-line system that meets the assumptions of M/M/1 has λ = 2, μ = 5. Calculate P₀. Build a table showing the probability of more than 0, 1, 2, 3, 4, 5, 6, and 7 units in the system. Round to six decimal places in your work