Question 1

Multiple-server queueing systems can perform satisfactorily with somewhat higher utilization factors than can single-server queueing systems.

Accepted Answer

A) True 
 B)False  True

Question 2

In a single-server system, the utilization factor is equal to the mean arrival rate divided by the mean service rate.

Accepted Answer

A) True 
 B)False  True

Question 3

Customers arrive at a suburban ticket outlet at the rate of 14 per hour on Monday mornings (exponential interarrival times). Selling the tickets and providing general information takes an average of 3 minutes per customer, and varies exponentially. There is 1 ticket agent on duty on Mondays.
How many minutes does the average customer wait in line?

Accepted Answer

A)  7 
B)  8 
C)  9 
D)  10 
E)  11 
A)  7 
B)  8 
C)  9 
D)  10 
E)  11 A

Question 4

Waiting lines occur even in systems that are less that 100% utilized because of variability in service rates and/or arrival rates.

Accepted Answer

A) True 
 B)False

Question 5

$\begin{array}{l}
\begin{array}{|l|l|}
\hline \text { Priority }&\text { Average Arrival Rate (exponential interarrival times) }\
\hline \text { High } & 3 \text { per hour } \
\hline \text { Low } & 5 \text { per hour } \
\hline
\end{array}
\end{array}$
$\begin{array}{|l|l|}
\hline Nurrber~ of~ servers:&5\
\hline Service~ rate:&2~ per~ hour ~(exponential ~service~ times)\
\hline 
\end{array}$
What is the average time in line (in minutes) for a high priority item?

Accepted Answer

A)  2 
B)  5 
C)  24 
D)  35 
E)  54 
A)  2 
B)  5 
C)  24 
D)  35 
E)  54

Question 6

Decreasing the variability of service times, without any change in the mean, improves the performance of a single-server queueing system substantially.

Accepted Answer

A) True 
 B)False

Question 7

The goal of queueing analysis is to minimize:

Accepted Answer

A)  the sum of customer waiting costs and service costs. 
B)  the sum of customer waiting time and service time. 
C)  service costs. 
D)  customer waiting time. 
E)  None of the answer choices is correct. 
A)  the sum of customer waiting costs and service costs. 
B)  the sum of customer waiting time and service time. 
C)  service costs. 
D)  customer waiting time. 
E)  None of the answer choices is correct.

Question 8

Customers filter into a record shop at an average of 1 per minute (exponential interarrivals) where the service rate is 15 per hour (exponential service times).
What is the minimum number of servers needed to keep the average time in the system under 6 minutes?

Accepted Answer

A)  2 
B)  3 
C)  4 
D)  5 
E)  6 
A)  2 
B)  3 
C)  4 
D)  5 
E)  6

Question 9

$\begin{array}{l}
\begin{array}{|l|l|}
\hline \text { Priority }&\text { Average Arrival Rate (exponential interarrival times) }\
\hline \text { High } & 3 \text { per hour } \
\hline \text { Low } & 5 \text { per hour } \
\hline
\end{array}
\end{array}$
$\begin{array}{|l|l|}
\hline Nurrber~ of~ servers:&5\
\hline Service~ rate:&2~ per~ hour ~(exponential ~service~ times)\
\hline 
\end{array}$
What is the overall arrival rate per hour?

Accepted Answer

A)  3 
B)  4 
C)  5 
D)  8 
E)  15 
A)  3 
B)  4 
C)  5 
D)  8 
E)  15

Question 10

Which of the following will equal the average time that a customer is in the system?
I. The average number in the system divided by the arrival rate.
II. The average number in the system multiplied by the arrival rate.
III. The average time in line plus the average service time.

Accepted Answer

A)  I only. 
B)  II only. 
C)  III only. 
D)  II and III only. 
E)  I and III only. 
A)  I only. 
B)  II only. 
C)  III only. 
D)  II and III only. 
E)  I and III only.

Question 11

$\begin{array}{l}
\begin{array}{|l|l|}
\hline \text { Priority }&\text { Average Arrival Rate (exponential interarrival times) }\
\hline \text { High } & 3 \text { per hour } \
\hline \text { Low } & 5 \text { per hour } \
\hline
\end{array}
\end{array}$
$\begin{array}{|l|l|}
\hline Nurrber~ of~ servers:&5\
\hline Service~ rate:&2~ per~ hour ~(exponential ~service~ times)\
\hline 
\end{array}$
What is the average time in the system (in minutes) for a low priority item?

Accepted Answer

A)  2 
B)  5 
C)  24 
D)  35 
E)  54 
A)  2 
B)  5 
C)  24 
D)  35 
E)  54

Question 12

During the early morning hours, customers arrive at a branch post office at the average rate of 45 per hour (exponential interarrival times), while clerks can handle transactions on an average of 4 minutes each (exponential).
If clerk cost is $30 per hour and customer waiting time represents a cost of $20 per hour, how many clerks can be justified on a cost basis?

Accepted Answer

A)  2. 
B)  3. 
C)  4. 
D)  5. 
E)  6. 
A)  2. 
B)  3. 
C)  4. 
D)  5. 
E)  6.

Question 13

Managers who oversee queueing systems are usually concerned with how many customers are waiting and how long they will have to wait.

Accepted Answer

A) True 
 B)False

Question 14

The exponential distribution will always provide a reasonably close approximation of the true service-time distribution.

Accepted Answer

A) True 
 B)False

Question 15

A single server queueing system has an average service time of 8 minutes and an average time between arrivals of 10 minutes. The arrival rate is:

Accepted Answer

A)  6 per hour. 
B)  7.5 per hour. 
C)  8 per hour. 
D)  10 per hour. 
E)  12.5 per hour. 
A)  6 per hour. 
B)  7.5 per hour. 
C)  8 per hour. 
D)  10 per hour. 
E)  12.5 per hour.

Question 16

A single-server queueing system has an average service time of 16 minutes per customer, which is exponentially distributed. The manager is thinking of converting to a system with a constant service time of 16 minutes. The arrival rate will remain the same. The effect will be to:

Accepted Answer

A)  increase the utilization factor. 
B)  decrease the utilization factor. 
C)  increase the average waiting time. 
D)  decrease the average waiting time. 
E)  not have any effect since the service time is unchanged. 
A)  increase the utilization factor. 
B)  decrease the utilization factor. 
C)  increase the average waiting time. 
D)  decrease the average waiting time. 
E)  not have any effect since the service time is unchanged.

Question 17

The term queue discipline refers to:

Accepted Answer

A)  the willingness of customers to wait in line for service. 
B)  having multiple waiting lines without customers switching from line to line. 
C)  the order in which customers are processed. 
D)  the reason waiting occurs in underutilized systems. 
E)  None of the answer choices is correct. 
A)  the willingness of customers to wait in line for service. 
B)  having multiple waiting lines without customers switching from line to line. 
C)  the order in which customers are processed. 
D)  the reason waiting occurs in underutilized systems. 
E)  None of the answer choices is correct.

Question 18

In a nonpreemptive priority system, customers are served in the order in which they arrive in the queue.

Accepted Answer

A) True 
 B)False

Question 19

$\begin{array}{l}
\begin{array}{|l|l|}
\hline \text { Priority }&\text { Average Arrival Rate (exponential interarrival times) }\
\hline \text { High } & 3 \text { per hour } \
\hline \text { Low } & 5 \text { per hour } \
\hline
\end{array}
\end{array}$
$\begin{array}{|l|l|}
\hline Nurrber~ of~ servers:&5\
\hline Service~ rate:&2~ per~ hour ~(exponential ~service~ times)\
\hline 
\end{array}$
What is the average number of low priority items waiting in line for service?

Accepted Answer

A)  0 
B)  0.24 
C)  1.74 
D)  1.98 
E)  2.22 
A)  0 
B)  0.24 
C)  1.74 
D)  1.98 
E)  2.22

Question 20

Which of these would increase system utilization?

Accepted Answer

A)  An increase in the service rate 
B)  An increase in the arrival rate 
C)  An increase in the number of servers 
D)  A decrease in service time 
E)  All of the answers choices are correct 
A)  An increase in the service rate 
B)  An increase in the arrival rate 
C)  An increase in the number of servers 
D)  A decrease in service time 
E)  All of the answers choices are correct

Multiple-server queueing systems can perform satisfactorily with somewhat higher utilization factors than can single-server queueing systems.

In a single-server system, the utilization factor is equal to the mean arrival rate divided by the mean service rate.

Waiting lines occur even in systems that are less that 100% utilized because of variability in service rates and/or arrival rates.

Decreasing the variability of service times, without any change in the mean, improves the performance of a single-server queueing system substantially.

The goal of queueing analysis is to minimize:

Customers filter into a record shop at an average of 1 per minute (exponential interarrivals) where the service rate is 15 per hour (exponential service times). What is the minimum number of servers needed to keep the average time in the system under 6 minutes?

Which of the following will equal the average time that a customer is in the system? I. The average number in the system divided by the arrival rate. II. The average number in the system multiplied by the arrival rate. III. The average time in line plus the average service time.

Managers who oversee queueing systems are usually concerned with how many customers are waiting and how long they will have to wait.

The exponential distribution will always provide a reasonably close approximation of the true service-time distribution.

A single server queueing system has an average service time of 8 minutes and an average time between arrivals of 10 minutes. The arrival rate is:

A single-server queueing system has an average service time of 16 minutes per customer, which is exponentially distributed. The manager is thinking of converting to a system with a constant service time of 16 minutes. The arrival rate will remain the same. The effect will be to:

The term queue discipline refers to:

In a nonpreemptive priority system, customers are served in the order in which they arrive in the queue.

Which of these would increase system utilization?

Introduction

Linear Programming: Basic Concepts

Linear Programming: Formulation and Applications

The Art of Modeling With Spreadsheets

What-If Analysis for Linear Programming

Network Optimization Problems

Using Binary Integer Programming to Deal With Yes-Or-No Decisions

Nonlinear Programming

Decision Analysis

Forecasting

Computer Simulation: Basic Concepts

Computer Simulation With Analytic Solver

Filters

Exam 11: Queueing Models

Multiple-server queueing systems can perform satisfactorily with somewhat higher utilization factors than can single-server queueing systems.

In a single-server system, the utilization factor is equal to the mean arrival rate divided by the mean service rate.

Waiting lines occur even in systems that are less that 100% utilized because of variability in service rates and/or arrival rates.

Decreasing the variability of service times, without any change in the mean, improves the performance of a single-server queueing system substantially.

The goal of queueing analysis is to minimize:

Customers filter into a record shop at an average of 1 per minute (exponential interarrivals) where the service rate is 15 per hour (exponential service times). What is the minimum number of servers needed to keep the average time in the system under 6 minutes?

Which of the following will equal the average time that a customer is in the system? I. The average number in the system divided by the arrival rate. II. The average number in the system multiplied by the arrival rate. III. The average time in line plus the average service time.

Managers who oversee queueing systems are usually concerned with how many customers are waiting and how long they will have to wait.

The exponential distribution will always provide a reasonably close approximation of the true service-time distribution.

A single server queueing system has an average service time of 8 minutes and an average time between arrivals of 10 minutes. The arrival rate is:

A single-server queueing system has an average service time of 16 minutes per customer, which is exponentially distributed. The manager is thinking of converting to a system with a constant service time of 16 minutes. The arrival rate will remain the same. The effect will be to:

The term queue discipline refers to:

In a nonpreemptive priority system, customers are served in the order in which they arrive in the queue.

Which of these would increase system utilization?

Introduction

Linear Programming: Basic Concepts

Linear Programming: Formulation and Applications

The Art of Modeling With Spreadsheets

What-If Analysis for Linear Programming

Network Optimization Problems

Using Binary Integer Programming to Deal With Yes-Or-No Decisions

Nonlinear Programming

Decision Analysis

Forecasting

Computer Simulation: Basic Concepts

Computer Simulation With Analytic Solver

Filters