Question 1

A university has only one technician in the repair station to care for the computers in the student labs. This system is most likely

Accepted Answer

A)  a single channel, limited queue system 
B)  a single channel, limited population system 
C)  a multi-channel, limited queue system 
D)  a multi-channel, limited population system 
E)  none of the above 
A)  a single channel, limited queue system 
B)  a single channel, limited population system 
C)  a multi-channel, limited queue system 
D)  a multi-channel, limited population system 
E)  none of the above B

Question 2

A queuing model which follows the M/M/1 assumptions has λ = 2 and μ = 8. The average number in the system Ls is __________ and the utilization of the system is __________.

Accepted Answer

A)  3; 100 percent 
B)  0.33; 25 percent 
C)  4; 33 percent 
D)  6; 25 percent 
E)  4; 25 percent 
A)  3; 100 percent 
B)  0.33; 25 percent 
C)  4; 33 percent 
D)  6; 25 percent 
E)  4; 25 percent B

Question 3

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

Accepted Answer

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

Question 4

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?

Accepted Answer

(a) Pₒ = 1 - 3/4 = 0.25; (b) The dentist

Question 5

Which of the following is a measure of queue performance?

Accepted Answer

A)  utilization factor 
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 the above 
A)  utilization factor 
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 the above

Question 6

A(n) __________ queuing system has one waiting line, but several servers; a(n) __________ queuing system is one in which the customer receives services from several stations before exiting the system

Accepted Answer

multiple-c

Question 7

A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of λ = 8 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 probability that the system is empty?
b. What is the probability that there is precisely one vehicle in the system?
c. What is the probability that there is more than one vehicle in the system?
d. What is the probability of 5 or more vehicles in the system?

Accepted Answer

(a) P0 = 1 - 8/10 = 0.20; (b)

Question 8

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 a

Accepted Answer

A)  multi-channel, limited queue length 
B)  single-channel, multi-phase, limited queue length 
C)  multi-channel, unlimited queue length 
D)  multiple single-channel systems, limited queue length 
E)  single-channel, unlimited queue length 
A)  multi-channel, limited queue length 
B)  single-channel, multi-phase, limited queue length 
C)  multi-channel, unlimited queue length 
D)  multiple single-channel systems, limited queue length 
E)  single-channel, unlimited queue length

Question 9

A university has several technicians in the repair station to care for the computers in the student labs. This system is most likely

Accepted Answer

A)  single channel, limited queue system 
B)  single channel, limited population system 
C)  multi-channel, limited queue system 
D)  multi-channel, limited population system 
E)  none of the above 
A)  single channel, limited queue system 
B)  single channel, limited population system 
C)  multi-channel, limited queue system 
D)  multi-channel, limited population system 
E)  none of the above

Question 10

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 11

Little's Law is not applicable in which of the following situations?

Accepted Answer

A)  the opening of a toy store on Black Friday morning 
B)  a 24-hour supermarket 
C)  a gas station with 24-hour self-service pumps 
D)  B and C 
E)  It is applicable to A, B, and C. 
A)  the opening of a toy store on Black Friday morning 
B)  a 24-hour supermarket 
C)  a gas station with 24-hour self-service pumps 
D)  B and C 
E)  It is applicable to A, B, and C.

Question 12

If the service time within a queuing system is constant, the service rate can be easily described by a negative exponential distribution.

Accepted Answer

A) True 
 B)False

Question 13

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

Accepted Answer

A)  0.75; 0.25 
B)  0.80; .20 
C)  -3; -4 
D)  3; 4 
E)  none of these 
A)  0.75; 0.25 
B)  0.80; .20 
C)  -3; -4 
D)  3; 4 
E)  none of these

Question 14

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. The average time a unit spends in this system

Accepted Answer

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

Question 15

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

Accepted Answer

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

Question 16

A waiting line meeting the assumptions of M/M/1 has average time between arrivals of 20 minutes and services items in an average of 10 minutes each; the utilization factor is approximately

Accepted Answer

A)  0.25 
B)  0.33 
C)  0.50 
D)  0.67 
E)  3.00 
A)  0.25 
B)  0.33 
C)  0.50 
D)  0.67 
E)  3.00

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

A copy center has five machines that serve many customers throughout the day; the waiting-line system for copy service has an infinite population while the waiting-line system for copier maintenance has a finite population

Accepted Answer

A) True 
 B)False

Question 19

A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of λ = 7 vehicles per day (approximately Poisson in nature). The mechanic crew can service an average of μ= 11 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 waiting for service at any one time?

Accepted Answer

(a) Utilization is ρ = 7 / 11

Question 20

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, which are

Accepted Answer

A)  normal arrivals, FIFO discipline, and normal service times 
B)  Poisson arrivals, FIFO discipline, and a single-service phase 
C)  Poisson arrivals, FIFO discipline, and exponential service times 
D)  Poisson arrivals, no queue discipline, and exponential service times 
E)  none of these 
A)  normal arrivals, FIFO discipline, and normal service times 
B)  Poisson arrivals, FIFO discipline, and a single-service phase 
C)  Poisson arrivals, FIFO discipline, and exponential service times 
D)  Poisson arrivals, no queue discipline, and exponential service times 
E)  none of these

Exam 24: Waiting-Line Models

A university has only one technician in the repair station to care for the computers in the student labs. This system is most likely

A queuing model which follows the M/M/1 assumptions has λ = 2 and μ = 8. The average number in the system Ls is __________ and the utilization of the system is __________.

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

Which of the following is a measure of queue performance?

A(n) __________ queuing system has one waiting line, but several servers; a(n) __________ queuing system is one in which the customer receives services from several stations before exiting the system

A university has several technicians in the repair station to care for the computers in the student labs. This system is most likely

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

Little's Law is not applicable in which of the following situations?

If the service time within a queuing system is constant, the service rate can be easily described by a negative exponential distribution.

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

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. The average time a unit spends in this system

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

A waiting line meeting the assumptions of M/M/1 has average time between arrivals of 20 minutes and services items in an average of 10 minutes each; the utilization factor is approximately

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

A copy center has five machines that serve many customers throughout the day; the waiting-line system for copy service has an infinite population while the waiting-line system for copier maintenance has a finite population

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, which are

Operations and Productivity

Operations Strategy in a Global Environment

Project Management

Forecasting

Design of Goods and Services

Managing Quality

Statistical Process Control

Process Strategy

Capacity and Constraint Management

Location Strategies

Layout Strategies

Human Resources, Job Design, and Work Measurement

Supply-Chain Management

Outsourcing as a Supply-Chain Strategy

Inventory Management

Aggregate Planning

Material Requirements Planning MRP and ERP

Short-Term Scheduling

Just-In-Time and Lean Options

Maintenance and Reliability

Decision-Making Tools

Linear Programming

Transportation Models

Learning Curves

Simulation

Filters

A queuing model which follows the M/M/1 assumptions has λ = 2 and μ = 8. The average number in the system Ls is and the utilization of the system is .

A(n) queuing system has one waiting line, but several servers; a(n) queuing system is one in which the customer receives services from several stations before exiting the system

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