Question 1

In queuing problems,which of the following probability distributions is typically used to describe the time to perform the service?

Accepted Answer

A) binomial 
B) normal 
C) Poisson 
D) negative exponential 
E) lognormal 
A) binomial 
B) normal 
C) Poisson 
D) negative exponential 
E) lognormal

Question 2

In the analysis of queuing models,the Poisson distribution often describes arrival rates and service times are often described by the negative exponential distribution.

Accepted Answer

A) True 
 B)False

Question 3

The common measures of a queuing system's performance include

Accepted Answer

A) probability that the service facility will be idle,average queue length,probability that the waiting time will exceed a specified duration. 
B) average time each customer spends in the system,probability that the service system will be idle,average time each customer spends in the queue. 
C) average queue length,maximum time a customer may spend in the queue,the utilization factor for the system. 
D) average time each customer spends in the system,maximum queue length,probability of a specific number of customers in the system. 
E) average time that the service facility is idle,minimum queue length,probability that the waiting time will exceed a specified duration. 
A) probability that the service facility will be idle,average queue length,probability that the waiting time will exceed a specified duration. 
B) average time each customer spends in the system,probability that the service system will be idle,average time each customer spends in the queue. 
C) average queue length,maximum time a customer may spend in the queue,the utilization factor for the system. 
D) average time each customer spends in the system,maximum queue length,probability of a specific number of customers in the system. 
E) average time that the service facility is idle,minimum queue length,probability that the waiting time will exceed a specified duration.

Question 4

As the average service rate μ increases,the shape of the negative exponential distribution of service times

Accepted Answer

A) grows steadily steeper without limit. 
B) has an ever steeper slope that eventually turns positive. 
C) becomes less gently curved as it moves ever closer to the graph origin. 
D) takes on a more uniform slope over a wide range of service times. 
E) changes in appearance from convex to concave. 
A) grows steadily steeper without limit. 
B) has an ever steeper slope that eventually turns positive. 
C) becomes less gently curved as it moves ever closer to the graph origin. 
D) takes on a more uniform slope over a wide range of service times. 
E) changes in appearance from convex to concave.

Question 5

Balk and renege are elements of queue discipline.

Accepted Answer

A) True 
 B)False

Question 6

A waiting-line system with one waiting line and three sequential processing stages is a multi-channel single-phase system.

Accepted Answer

A) True 
 B)False

Question 7

A queuing model which follows the M/M/1 assumptions has λ = 3 and μ = 2.The average number in the system is

Accepted Answer

A) -3. 
B) 3. 
C) 0.667. 
D) 150%. 
E) growing without limit,since λ is larger than μ. 
A) -3. 
B) 3. 
C) 0.667. 
D) 150%. 
E) growing without limit,since λ is larger than μ.

Question 8

A single-phase waiting-line system meets the assumptions of constant service time or M/D/1.Units arrive at this system every 12 minutes on average.Service takes a constant 8 minutes.The average number in the system Ls is approximately

Accepted Answer

A) 2.25. 
B) 2.5. 
C) 3.0. 
D) 1.33. 
E) 5.0. 
A) 2.25. 
B) 2.5. 
C) 3.0. 
D) 1.33. 
E) 5.0.

Question 9

Why does it matter whether a population of arrivals is limited or unlimited? Compose your answer in a well-organized,convincing paragraph.

Accepted Answer

If an arrival population is unlimited,th

Question 10

A queuing model which follows the M/M/1 assumptions has λ = 2 and μ = 3.The average number in the system is

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 11

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 12

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 = 11 vehicles per day with a repair time distribution that approximates an exponential distribution.The crew cost is approximately $300 per day.The cost associated with lost productivity from the breakdown is estimated at $150 per vehicle per day (or any fraction thereof).What is the expected cost of this system?

Accepted Answer

The number of vehicles out of

Question 13

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 14

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 15

A finite population waiting line model has an average service time T of 100 minutes and an average time between service requirements U of 400 minutes;the service factor X is 0.25.

Accepted Answer

A) True 
 B)False

Question 16

A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of λ = 7.5 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 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 in the system at any one time?

Accepted Answer

(a)Utilization is ρ = 7.5 / 10

Question 17

A waiting-line system that meets the assumptions of M/M/1 has = 1,= 4.Calculate Po.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

The answer of A waiting-line system that meets the assumptions...

Question 18

A finite population waiting line model has an average service time T of 100 minutes and an average time between service requirements U of 400 minutes;the service factor X is

Accepted Answer

A) 0.20. 
B) 0.25. 
C) 4. 
D) 5. 
E) 300 minutes. 
A) 0.20. 
B) 0.25. 
C) 4. 
D) 5. 
E) 300 minutes.

Question 19

A manufacturing plant is trying to determine how long the average line for a repair process will be.If 10 machines arrive each hour and must wait 6 minutes in the line,how long will the line be,on average?

Accepted Answer

Little's Law X machines = 10 m

Question 20

An airline ticket counter,with several agents for one line of customers,is an example of a

Accepted Answer

A) single channel,single phase system. 
B) single channel,multi-phase system. 
C) multi-channel,single phase system. 
D) multi-channel,multi-phase system. 
E) multi-channel,cross-phase system. 
A) single channel,single phase system. 
B) single channel,multi-phase system. 
C) multi-channel,single phase system. 
D) multi-channel,multi-phase system. 
E) multi-channel,cross-phase system.

Exam 24: Waiting-Line Models

In queuing problems,which of the following probability distributions is typically used to describe the time to perform the service?

In the analysis of queuing models,the Poisson distribution often describes arrival rates and service times are often described by the negative exponential distribution.

The common measures of a queuing system's performance include

As the average service rate μ increases,the shape of the negative exponential distribution of service times

Balk and renege are elements of queue discipline.

A waiting-line system with one waiting line and three sequential processing stages is a multi-channel single-phase system.

A queuing model which follows the M/M/1 assumptions has λ = 3 and μ = 2.The average number in the system is

A single-phase waiting-line system meets the assumptions of constant service time or M/D/1.Units arrive at this system every 12 minutes on average.Service takes a constant 8 minutes.The average number in the system Ls is approximately

Why does it matter whether a population of arrivals is limited or unlimited? Compose your answer in a well-organized,convincing paragraph.

A queuing model which follows the M/M/1 assumptions has λ = 2 and μ = 3.The average number in the system is

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.

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.

A finite population waiting line model has an average service time T of 100 minutes and an average time between service requirements U of 400 minutes;the service factor X is 0.25.

A waiting-line system that meets the assumptions of M/M/1 has = 1,= 4.Calculate Po.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

A finite population waiting line model has an average service time T of 100 minutes and an average time between service requirements U of 400 minutes;the service factor X is

A manufacturing plant is trying to determine how long the average line for a repair process will be.If 10 machines arrive each hour and must wait 6 minutes in the line,how long will the line be,on average?

An airline ticket counter,with several agents for one line of customers,is an example of a

Operations and Productivity

Operations Strategy in a Global Environment

Project Management

Forecasting

Sustainability in the Supply Chain and Design of Goods and Services

Managing Quality

Process Strategy and Sustainability

Location Strategies

Layout Strategies

Human Resources,job Design,and Work Measurement

Supply-Chain Management

Inventory Management

Aggregate Planning

Material Requirements Planning Mrpand ERP

Short-Term Scheduling

Jit and Lean Operations

Maintenance and Reliability

Statistical Process Control

Capacity and Constraint Management

Supply Chain Management Analytics

Decision-Making Tools

Linear Programming

Transportation Models

Learning Curves

Simulation

Filters