Question 1

Balk and renege are elements of queue discipline.

Accepted Answer

A) True 
 B)False  False

Question 2

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 the above 
A) 0.75;0.25 
B) 0.80;.20 
C) -3;-4 
D) 3;4 
E) none of the above A

Question 3

A queuing model that follows the M/M/1 assumptions has λ = 2 and μ = 8.The average number in the system Ls is ________ and the utilization of the system is ________.

Accepted Answer

A) 3;100 percent 
B) 0.33;25 percent 
C) 4;33 percent 
D) 6;25 percent 
E) 4;25 percent 
A) 3;100 percent 
B) 0.33;25 percent 
C) 4;33 percent 
D) 6;25 percent 
E) 4;25 percent B

Question 4

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 probability distribution. 
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 probability distribution.

Question 5

A waiting-line system with one waiting line and three sequential processing stages is a multiple-server,single-phase system.

Accepted Answer

A) True 
 B)False

Question 6

A(n)________ queuing system is one in which the customer receives service from only one station and then exits the system.

Accepted Answer

The answer of A(n)________ queuing system is one in which...

Question 7

A(n)________ is a discrete probability distribution that often describes the arrival rate in queuing theory.

Accepted Answer

Poisson di

Question 8

Which of the following is NOT a common queuing situation?

Accepted Answer

A) grocery shoppers being served by checkout clerks 
B) commuters slowing or stopping at toll plazas to pay highway tolls 
C) machinery waiting to be repaired or maintained 
D) parcel delivery truck following its computer-generated route 
E) patients in a health clinic waiting to see one of several doctors 
A) grocery shoppers being served by checkout clerks 
B) commuters slowing or stopping at toll plazas to pay highway tolls 
C) machinery waiting to be repaired or maintained 
D) parcel delivery truck following its computer-generated route 
E) patients in a health clinic waiting to see one of several doctors

Question 9

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 140 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?

Accepted Answer

(a)The utilization rate is = 1

Question 10

Students arrive randomly at the help desk of the computer lab.There is only one service agent,and the time required for inquiry varies from student to student.Arrival rates have been found to follow the Poisson distribution,and the service times follow the negative exponential distribution.The average arrival rate is 12 students per hour,and the average service rate is 20 students per hour.On average,how long does it take to service each student?

Accepted Answer

A) 1 minute 
B) 2 minutes 
C) 3 minutes 
D) 5 minutes 
E) 20 minutes 
A) 1 minute 
B) 2 minutes 
C) 3 minutes 
D) 5 minutes 
E) 20 minutes

Question 11

Suppose that a fast food restaurant wants the average line to be 4 customers and that 80 customers arrive each hour.How many minutes will the average customer be forced to wait in line?

Accepted Answer

Little's Law: 4 customers = (8

Question 12

A queuing model that follows the M/M/1 assumptions has λ = 3 and μ = 2.What is the average number of units in the system?

Accepted Answer

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

Question 13

A(n)________ queuing system has one line and one server.

Accepted Answer

The answer of A(n)________ queuing system has one line and...

Question 14

A college registrar's office requires you to first visit with one of three advisors and then with one of two financial professionals.This system is best described as which of the following?

Accepted Answer

A) single-server,single-phase system 
B) single-server,multiphase system 
C) multiple-server,single-phase system 
D) multiple-server,multiphase system 
E) multiple-server,cross-phase system 
A) single-server,single-phase system 
B) single-server,multiphase system 
C) multiple-server,single-phase system 
D) multiple-server,multiphase system 
E) multiple-server,cross-phase system

Question 15

A single-phase waiting-line system meets the assumptions of constant service time or M/D/1.Units arrive at this system every 10 minutes on average.Service takes a constant 4 minutes.What is the average length of the queue Lq in units?

Accepted Answer

A) 0.4 
B) 0.133 
C) 4.167 
D) 4.583 
E) 6 
A) 0.4 
B) 0.133 
C) 4.167 
D) 4.583 
E) 6

Question 16

Arrivals or inputs to a waiting-line system have characteristics that include:

Accepted Answer

A) population size. 
B) population behavior. 
C) population's statistical distribution. 
D) A and C 
E) A,B,and C 
A) population size. 
B) population behavior. 
C) population's statistical distribution. 
D) A and C 
E) A,B,and C

Question 17

Students arrive randomly at the help desk of the computer lab.There is only one service agent,and the time required for inquiry varies from student to student.Arrival rates have been found to follow the Poisson distribution,and the service times follow the negative exponential distribution.The average arrival rate is 12 students per hour,and the average service rate is 20 students per hour.How many students,on average,will be waiting in line at any one time?

Accepted Answer

A) 0.9 students 
B) 1.5 students 
C) 3 students 
D) 4 students 
E) 36 students 
A) 0.9 students 
B) 1.5 students 
C) 3 students 
D) 4 students 
E) 36 students

Question 18

What does it mean to have a patient customer in a waiting line?

Accepted Answer

A patient customer is one who

Question 19

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 20

A copy center has five machines that serve many customers throughout the day.The waiting-line system for copy service has an infinite population,while the waiting-line system for copier maintenance has a finite population

Accepted Answer

A) True 
 B)False

Exam 25: Waiting-Line Models

Balk and renege are elements of queue discipline.

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 ________.

A queuing model that follows the M/M/1 assumptions has λ = 2 and μ = 8.The average number in the system Ls is ________ and the utilization of the system is ________.

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

A waiting-line system with one waiting line and three sequential processing stages is a multiple-server,single-phase system.

A(n)________ queuing system is one in which the customer receives service from only one station and then exits the system.

A(n)________ is a discrete probability distribution that often describes the arrival rate in queuing theory.

Which of the following is NOT a common queuing situation?

Suppose that a fast food restaurant wants the average line to be 4 customers and that 80 customers arrive each hour.How many minutes will the average customer be forced to wait in line?

A queuing model that follows the M/M/1 assumptions has λ = 3 and μ = 2.What is the average number of units in the system?

A(n)________ queuing system has one line and one server.

A college registrar's office requires you to first visit with one of three advisors and then with one of two financial professionals.This system is best described as which of the following?

A single-phase waiting-line system meets the assumptions of constant service time or M/D/1.Units arrive at this system every 10 minutes on average.Service takes a constant 4 minutes.What is the average length of the queue Lq in units?

Arrivals or inputs to a waiting-line system have characteristics that include:

What does it mean to have a patient customer in a waiting line?

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 copy center has five machines that serve many customers throughout the day.The waiting-line system for copy service has an infinite population,while the waiting-line system for copier maintenance has a finite population

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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 .

A queuing model that follows the M/M/1 assumptions has λ = 2 and μ = 8.The average number in the system Ls is and the utilization of the system is .