Question 1

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) a multi-channel,unlimited population system. 
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) a multi-channel,unlimited population system.

Question 2

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 3

Which one of the following is not a characteristic of a Model B or M/M/S system?

Accepted Answer

A) unlimited population size 
B) single channel 
C) single queue 
D) single phase 
E) Poisson arrival rate pattern 
A) unlimited population size 
B) single channel 
C) single queue 
D) single phase 
E) Poisson arrival rate pattern

Question 4

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 5

A waiting line meeting the M/M/1 assumptions has an arrival rate of 10 per hour and a service rate of 12 per hour.What is the average time a unit spends in the system and the average time a unit spends waiting?

Accepted Answer

Ws = 1 / (μ - λ)= 1

Question 6

In a repetitive focus factory,the number of phases found in the system might refer to

Accepted Answer

A) the number of successive operations that have to be performed on a part. 
B) the number of machines doing the same necessary operations. 
C) the number of parts waiting to be processed. 
D) the number of workers waiting to perform their task. 
E) the number of units with defects requiring rework. 
A) the number of successive operations that have to be performed on a part. 
B) the number of machines doing the same necessary operations. 
C) the number of parts waiting to be processed. 
D) the number of workers waiting to perform their task. 
E) the number of units with defects requiring rework.

Question 7

An M/M/1 model and an M/D/1 model each have an arrival rate of 1 per minute and a service rate of 3 per minute;the average queue length of the M/M/1 will be twice that of the M/D/1.

Accepted Answer

A) True 
 B)False

Question 8

If the food service for the university operates a cafeteria with a single serving line,that system behaves most like 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.

Question 9

Which of the following represents a customer that reneged due to the waiting-line?

Accepted Answer

A) A husband and wife decide to eat out instead after seeing the movie ticket line. 
B) A car drives past the first fast-food restaurant on Hamburger Row because the drive-through was full. 
C) A Black Friday shopper skipped one store because the line went around the building. 
D) A student ordered pizza online because the phone line was busy. 
E) A customer at a gas station went inside to buy a soda,but after waiting in line for a minute left the soda behind and went outside empty-handed. 
A) A husband and wife decide to eat out instead after seeing the movie ticket line. 
B) A car drives past the first fast-food restaurant on Hamburger Row because the drive-through was full. 
C) A Black Friday shopper skipped one store because the line went around the building. 
D) A student ordered pizza online because the phone line was busy. 
E) A customer at a gas station went inside to buy a soda,but after waiting in line for a minute left the soda behind and went outside empty-handed.

Question 10

A bank office with five tellers,each with a separate line of customers,exhibits the characteristics of a multi-phase queuing system.

Accepted Answer

A) True 
 B)False

Question 11

Which of the following represents an unlimited queue?

Accepted Answer

A) drive-through lane at a fast-food restaurant 
B) small barbershop with only 5 chairs for waiting customers 
C) toll booth serving automobiles on an interstate 
D) faculty office with limited seating during office hours 
E) restaurant with no outside seating and limited capacity due to fire department restrictions 
A) drive-through lane at a fast-food restaurant 
B) small barbershop with only 5 chairs for waiting customers 
C) toll booth serving automobiles on an interstate 
D) faculty office with limited seating during office hours 
E) restaurant with no outside seating and limited capacity due to fire department restrictions

Question 12

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 i

Question 13

Which of the following is most likely to violate a FIFO queue?

Accepted Answer

A) supermarket with no express lanes 
B) car repair garage 
C) emergency room 
D) fast-food restaurant 
E) coffee shop 
A) supermarket with no express lanes 
B) car repair garage 
C) emergency room 
D) fast-food restaurant 
E) coffee shop

Question 14

The shopper who says to himself,"I've waited too long in this line.I don't really need to buy this product today," and leaves the store is an illustration of which element of arrival behavior?

Accepted Answer

A) random arrival 
B) renege 
C) random departure 
D) balk 
E) sour grapes 
A) random arrival 
B) renege 
C) random departure 
D) balk 
E) sour grapes

Question 15

Which of the following is not an assumption of the M/M/1 model?

Accepted Answer

A) The first customers to arrive are the first customers served. 
B) Each arrival comes independently of the arrival immediately before and after that arrival. 
C) The population from which the arrivals come is very large or infinite in size. 
D) Customers do not renege. 
E) Service times occur according to a normal curve. 
A) The first customers to arrive are the first customers served. 
B) Each arrival comes independently of the arrival immediately before and after that arrival. 
C) The population from which the arrivals come is very large or infinite in size. 
D) Customers do not renege. 
E) Service times occur according to a normal curve.

Question 16

Study of waiting-line models helps operations managers better understand

Accepted Answer

A) service systems such as bank teller stations. 
B) maintenance activities that might repair broken machinery. 
C) shop-floor control activities. 
D) service systems such as amusement park rides. 
E) all of the above. 
A) service systems such as bank teller stations. 
B) maintenance activities that might repair broken machinery. 
C) shop-floor control activities. 
D) service systems such as amusement park rides. 
E) all of the above.

Question 17

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 18

At the order fulfillment center of a major mail-order firm,customer orders,already packaged for shipment,arrive at the sorting machine to be sorted for loading onto the appropriate truck for the parcel's address.The arrival rate at the sorting machine is at the rate of 100 per hour following a Poisson distribution.The machine sorts at the constant rate of 150 per hour.
a.What is the utilization rate of the system?
b.What is the average number of packages waiting to be sorted?
c.What is the average number of packages in the sorting system?
d.How long must the average package wait until it gets sorted?
e.What would Lq and Wq be if the service rate were exponential,not constant?

Accepted Answer

(a)The utilization rate is = 100/150 = 0

Question 19

Students arrive randomly at the help desk of a computer lab.There is only one service agent,and the service time varies from one student to the other.Provide the most likely characteristics for this system.
a.name of model
b.number of channels
c.number of phases
d.arrival rate distribution
e.service time distribution
f.population size
g.queue discipline

Accepted Answer

Single channel syste

Question 20

What is queue discipline? State three rules for queue discipline.Which of these rules appears most frequently in the four main models?

Accepted Answer

Queue discipline is the rule that determ

Exam 24: Waiting-Line Models

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

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

Which one of the following is not a characteristic of a Model B or M/M/S system?

A waiting line meeting the M/M/1 assumptions has an arrival rate of 10 per hour and a service rate of 12 per hour.What is the average time a unit spends in the system and the average time a unit spends waiting?

In a repetitive focus factory,the number of phases found in the system might refer to

An M/M/1 model and an M/D/1 model each have an arrival rate of 1 per minute and a service rate of 3 per minute;the average queue length of the M/M/1 will be twice that of the M/D/1.

If the food service for the university operates a cafeteria with a single serving line,that system behaves most like a

Which of the following represents a customer that reneged due to the waiting-line?

A bank office with five tellers,each with a separate line of customers,exhibits the characteristics of a multi-phase queuing system.

Which of the following represents an unlimited queue?

Which of the following is most likely to violate a FIFO queue?

The shopper who says to himself,"I've waited too long in this line.I don't really need to buy this product today," and leaves the store is an illustration of which element of arrival behavior?

Which of the following is not an assumption of the M/M/1 model?

Study of waiting-line models helps operations managers better understand

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 ________.

What is queue discipline? State three rules for queue discipline.Which of these rules appears most frequently in the four main models?

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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 .