Question 1

When simulation is used for relatively small values of time,Little's formula holds only approximately.

Accepted Answer

A) True 
 B)False  True

Question 2

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

Accepted Answer

A) True 
 B)False  False

Question 3

Exhibit 13-4
Consider 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 customers that do not wait = 1 - % who do wait = 1 - 65.8% = 34.2%

Question 4

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

Accepted Answer

A) True 
 B)False

Question 5

Exhibit 13-1
A 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 1] Refer to Exhibit 13-1.Is it reasonable to assume exponentially distributed interarrival times for the grocery store customers? If so,what is $\lambda$?

Accepted Answer

The histogram of the data (sho

Question 6

Exponentially distributed service times are often more realistic than exponentially distributed interarrival times.

Accepted Answer

A) True 
 B)False

Question 7

Exhibit 13-4
Consider 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 13-2
An 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

L_s = @#LAT-DLM& * W

Question 9

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 10

The exponential distribution is:

Accepted Answer

A)  flat 
B)  bell-shaped 
C)  heavily right-skewed 
D)  heavily left-skewed 
A)  flat 
B)  bell-shaped 
C)  heavily right-skewed 
D)  heavily left-skewed

Question 11

As the traffic intensity approaches 1:

Accepted Answer

A)  there is no waiting 
B)  waiting lines stabilize 
C)  waiting lines grow extremely rapidly 
D)  at least one server will be idle 
A)  there is no waiting 
B)  waiting lines stabilize 
C)  waiting lines grow extremely rapidly 
D)  at least one server will be idle

Question 12

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

Question 13

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 14

Exhibit 13-1
A 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 $\lambda$ 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

=EXPONDIST(2,0.5,1)-

Question 15

Exhibit 13-3
A 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

@#LAT-DLM& = @#LAT-DLM& / @#LAT-DLM&= 24 / 30 = 0.8 L_S= @#LAT-DLM& /

Question 16

Exhibit 13-2
An 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.What is the server utilization?

Accepted Answer

U = L_s / s

Question 17

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 18

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 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

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

When simulation is used for relatively small values of time,Little's formula holds only approximately.

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

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

Exponentially distributed service times are often more realistic than exponentially distributed interarrival times.

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

The exponential distribution is:

As the traffic intensity approaches 1:

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

Traffic intensity is a very useful measure of:

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.

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

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.

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

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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Regression and Forecasting Models

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Exam 13: Queuing Models

When simulation is used for relatively small values of time,Little's formula holds only approximately.

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

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

Exponentially distributed service times are often more realistic than exponentially distributed interarrival times.

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

The exponential distribution is:

As the traffic intensity approaches 1:

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

Traffic intensity is a very useful measure of:

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.

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

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.

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

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 Models

Regression and Forecasting Models

Filters

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