Question 1

When a customer already in line in a queuing system becomes impatient and leaves the system before starting service, this is called:

Accepted Answer

A) balking 
B) limited waiting 
C) quitting 
D) reneging 
A) balking 
B) limited waiting 
C) quitting 
D) reneging D

Question 2

Which of the following is not one of the types of service disciplines?

Accepted Answer

A) Longest-processing-time 
B) First-come-first-served 
C) Service-in-random-order 
D) Last-come-first-served 
A) Longest-processing-time 
B) First-come-first-served 
C) Service-in-random-order 
D) Last-come-first-served A

Question 3

The mean and standard deviation of an exponential distribution are both equal to the parameter λ.

Accepted Answer

A) True 
 B)False  False

Question 4

In a process where interarrival times are exponentially distributed, the time since the last arrival is irrelevant.

Accepted Answer

A) True 
 B)False

Question 5

Exhibit 13-1A grocery store manager would like to use an analytical queueing model to study the lines of customers that form in front of the checkout stations in the store. During a period of time when business is steady, several store employees have gathered data on customer interarrival times, which are shown below.
  
-[Part 3] Refer to Exhibit 13-1. Again assuming an exponential distribution with the parameter λ you obtained in Part 2, what is the probability that a customer interarrival time will be more than 2 minutes, but less than 5 minutes?

Accepted Answer

=EXPON.DIST(5,0.2,TR

Question 6

Exhibit 13-1A grocery store manager would like to use an analytical queueing model to study the lines of customers that form in front of the checkout stations in the store. During a period of time when business is steady, several store employees have gathered data on customer interarrival times, which are shown below.
  
-[Part 2] Refer to Exhibit 13-1. Assuming an exponential distribution with the parameter λ you obtained in Part 1, what is the probability that a customer interarrival time will be less than 2 minutes?

Accepted Answer

=EXPON.DIS

Question 7

Exhibit 13-4Consider a fast-food restaurant where customers arrive at a Poisson rate of 100 per hour. Four equally capable servers work at the restaurant during a typical hour of operation. Each employee takes, on average, 2 minutes to serve a customer, and service times are exponentially distributed. Customers who arrive and find all 4 servers busy join a single queue and are then served in first-come-first-served fashion.
-Refer to Exhibit 13-4. Use the M/M/s template to find the expected number of busy servers, and the expected fraction of time each server is busy

Accepted Answer

The expected number of busy se

Question 8

Exhibit 13-3A Credit Union has a small branch in which a single customer service representative serves the needs of customers who arrive at an average rate of 24 per hour. The service representative can typically handle 30 customers per hour. Based on an analysis of historical data, it is reasonable to assume that customer interarrival times and service times are exponentially distributed. Assume that all arriving customers enter the branch, regardless of the number already waiting in line.
-Refer to Exhibit 13-3. What is the average length of time (in hours) spent waiting in line?

Accepted Answer

WQ = WS −

Question 9

In an Erlang loss model, customers who arrive when all servers are busy are lost to the system.

Accepted Answer

A) True 
 B)False

Question 10

Exhibit 13-2An oil-change facility serves customers that enter at a rate of 8 per hour. There are five servers available to perform oil changes for entering customers. Customers wait in a single line and enter the facility, in first-come-first-serve fashion, to the first of the five servers who is available. Each server can change the oil of one customer's car every 30 minutes on average.
-Refer to Exhibit 13-2. How many of the servers are busy on average?

Accepted Answer

Ls = λ * Ws = 8 * 0.

Question 11

Almost all queuing systems are alike in that customers enter a system, possibly wait in one or more queues, get served, and then depart.

Accepted Answer

A) True 
 B)False

Question 12

Traffic intensity is a very useful measure of:

Accepted Answer

A) whether the system is stable or not 
B) the number of customers in a system 
C) the distribution of interarrival times 
D) the amount of congestion in the system 
A) whether the system is stable or not 
B) the number of customers in a system 
C) the distribution of interarrival times 
D) the amount of congestion in the system

Question 13

The two basic modeling approaches for queuing systems are optimization and simulation.

Accepted Answer

A) True 
 B)False

Question 14

Which of the following is not one of the important issues defining types of arrivals in a queuing system?

Accepted Answer

A) Whether customers arrive one at a time or in batches. 
B) Whether customers are all essentially alike or are in separate priority classes. 
C) Whether customers have been through the system before or not 
D) Whether customers will wait in line or not 
A) Whether customers arrive one at a time or in batches. 
B) Whether customers are all essentially alike or are in separate priority classes. 
C) Whether customers have been through the system before or not 
D) Whether customers will wait in line or not

Question 15

In queuing systems with a finite number of customers allowed, there is no need to require that the traffic intensity be less than 1 to ensure stability.

Accepted Answer

A) True 
 B)False

Question 16

Exhibit 13-3A Credit Union has a small branch in which a single customer service representative serves the needs of customers who arrive at an average rate of 24 per hour. The service representative can typically handle 30 customers per hour. Based on an analysis of historical data, it is reasonable to assume that customer interarrival times and service times are exponentially distributed. Assume that all arriving customers enter the branch, regardless of the number already waiting in line.
-Refer to Exhibit 13-3. What is the average length of the waiting line?

Accepted Answer

ρ = λ / μ = 24 / 30 = 0.8
L =

Question 17

Exhibit 13-4Consider a fast-food restaurant where customers arrive at a Poisson rate of 100 per hour. Four equally capable servers work at the restaurant during a typical hour of operation. Each employee takes, on average, 2 minutes to serve a customer, and service times are exponentially distributed. Customers who arrive and find all 4 servers busy join a single queue and are then served in first-come-first-served fashion.
-Refer to Exhibit 13-4. What percentage of customers do not wait in the queue?

Accepted Answer

The expected % of cu

Question 18

The decision to balk at entering a queuing system can be made by the customer or the system.

Accepted Answer

A) True 
 B)False

Question 19

Congestion in a queuing system will be unaffected by changes in the variability of the interarrival time and service time distributions, as long as the distributions retain the same means.

Accepted Answer

A) True 
 B)False

Question 20

A requirement for steady state analysis of a queuing system is that:

Accepted Answer

A) the initial conditions are still in effect 
B) the waiting time must be exponentially distributed 
C) the analysis period is at least two hours 
D) the service rate must be constant 
A) the initial conditions are still in effect 
B) the waiting time must be exponentially distributed 
C) the analysis period is at least two hours 
D) the service rate must be constant

When a customer already in line in a queuing system becomes impatient and leaves the system before starting service, this is called:

Which of the following is not one of the types of service disciplines?

The mean and standard deviation of an exponential distribution are both equal to the parameter λ.

In a process where interarrival times are exponentially distributed, the time since the last arrival is irrelevant.

In an Erlang loss model, customers who arrive when all servers are busy are lost to the system.

Almost all queuing systems are alike in that customers enter a system, possibly wait in one or more queues, get served, and then depart.

Traffic intensity is a very useful measure of:

The two basic modeling approaches for queuing systems are optimization and simulation.

Which of the following is not one of the important issues defining types of arrivals in a queuing system?

In queuing systems with a finite number of customers allowed, there is no need to require that the traffic intensity be less than 1 to ensure stability.

The decision to balk at entering a queuing system can be made by the customer or the system.

Congestion in a queuing system will be unaffected by changes in the variability of the interarrival time and service time distributions, as long as the distributions retain the same means.

A requirement for steady state analysis of a queuing system is that:

Introduction to Modeling

Introduction to Spreadsheet Modeling

Introduction to Optimization Modeling

Linear Programming Models

Network Models

Optimization Models With Integer Variables

Nonlinear Optimization Models

Evolutionary Solver: An Alternative Optimization Procedure

Decision Making Under Uncertainty

Introduction to Simulation Modeling

Simulation Models

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Exam 13: Queuing Models

When a customer already in line in a queuing system becomes impatient and leaves the system before starting service, this is called:

Which of the following is not one of the types of service disciplines?

The mean and standard deviation of an exponential distribution are both equal to the parameter λ.

In a process where interarrival times are exponentially distributed, the time since the last arrival is irrelevant.

In an Erlang loss model, customers who arrive when all servers are busy are lost to the system.

Almost all queuing systems are alike in that customers enter a system, possibly wait in one or more queues, get served, and then depart.

Traffic intensity is a very useful measure of:

The two basic modeling approaches for queuing systems are optimization and simulation.

Which of the following is not one of the important issues defining types of arrivals in a queuing system?

In queuing systems with a finite number of customers allowed, there is no need to require that the traffic intensity be less than 1 to ensure stability.

The decision to balk at entering a queuing system can be made by the customer or the system.

Congestion in a queuing system will be unaffected by changes in the variability of the interarrival time and service time distributions, as long as the distributions retain the same means.

A requirement for steady state analysis of a queuing system is that:

Introduction to Modeling

Introduction to Spreadsheet Modeling

Introduction to Optimization Modeling

Linear Programming Models

Network Models

Optimization Models With Integer Variables

Nonlinear Optimization Models

Evolutionary Solver: An Alternative Optimization Procedure

Decision Making Under Uncertainty

Introduction to Simulation Modeling

Simulation Models

Inventory and Supply Chain Models

Regression and Forecasting Models

Filters