Question 1

In the basic queuing model (M/M/1), service times are described by

Accepted Answer

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

Question 2

A waiting line meeting the M/M/1 assumptions has an arrival rate of 4 per hour and a service rate of 12 per hour. What is the probability that the waiting line is empty?

Accepted Answer

Pₒ = 1 - λ

Question 3

"Women and children first!" declares the captain of a sinking ship. His directive employs which of the following queue disciplines in disembarking passengers?

Accepted Answer

A)  priority 
B)  random 
C)  FIFO or FIFS 
D)  LIFO or LIFS 
E)  SPT 
A)  priority 
B)  random 
C)  FIFO or FIFS 
D)  LIFO or LIFS 
E)  SPT

Question 4

A dental clinic at which only one dentist works is open only two days a week. During those two days, the traffic arrivals follow a Poisson distribution 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 is the probability that there are one or more patients in the system?
c. What is the probability that there are four patients in the system?
d. What is the probability that there are four or more patients in the system?

Accepted Answer

(a) Pₒ = 1 - 3/4 = 0.25; (b) The probabi

Question 5

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 6

A waiting line has a(n) __________ population if, as arrivals take place, the likelihood of additional arrivals is decreased.

Accepted Answer

The answer of A waiting line has a(n) __________ population...

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)  none of the above 
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)  none of the above

Question 9

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 10

Suppose that customer arrivals are governed by a Poisson distribution. If the average arrival rate is 60 customers each hour, how many times will 60 customers arrive during a one hour period for each time that only 40 customers arrive.

Accepted Answer

P(60)=e^-60*60^60/ 6

Question 11

A waiting-line system has three parts: the size of the arrival population, the behavior of arrivals, and the statistical distribution of arrivals.

Accepted Answer

A) True 
 B)False

Question 12

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 13

In queuing problems, arrival rates are generally described by the normal probability distribution.

Accepted Answer

A) True 
 B)False

Question 14

Which one of the following is not a characteristic of a Model A or M/M/1 system?

Accepted Answer

A)  exponential service time pattern 
B)  single number of channels 
C)  single number of phases 
D)  Poisson arrival rate pattern 
E)  limited population size 
A)  exponential service time pattern 
B)  single number of channels 
C)  single number of phases 
D)  Poisson arrival rate pattern 
E)  limited population size

Question 15

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 16

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, t

Question 17

The study of waiting lines calculates the cost of providing good service but does not value the cost of customers' waiting time.

Accepted Answer

A) True 
 B)False

Question 18

A queuing model which follows the M/M/1 assumptions has λ = 2 and μ = 3. The average waiting time 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 19

A(n) __________ occurs when an arrival refuses to enter a waiting line; a(n) __________ occurs when an arrival joins a waiting line, then leaves it.

Accepted Answer

The answer of A(n) __________ occurs when an arrival refuses...

Question 20

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

Exam 24: Waiting-Line Models

In the basic queuing model (M/M/1), service times are described by

A waiting line meeting the M/M/1 assumptions has an arrival rate of 4 per hour and a service rate of 12 per hour. What is the probability that the waiting line is empty?

"Women and children first!" declares the captain of a sinking ship. His directive employs which of the following queue disciplines in disembarking passengers?

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

A waiting line has a(n) __________ population if, as arrivals take place, the likelihood of additional arrivals is decreased.

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

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

Suppose that customer arrivals are governed by a Poisson distribution. If the average arrival rate is 60 customers each hour, how many times will 60 customers arrive during a one hour period for each time that only 40 customers arrive.

A waiting-line system has three parts: the size of the arrival population, the behavior of arrivals, and the statistical distribution of arrivals.

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

In queuing problems, arrival rates are generally described by the normal probability distribution.

Which one of the following is not a characteristic of a Model A or M/M/1 system?

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

The study of waiting lines calculates the cost of providing good service but does not value the cost of customers' waiting time.

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

A(n) __________ occurs when an arrival refuses to enter a waiting line; a(n) __________ occurs when an arrival joins a waiting line, then leaves it.

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

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A(n) occurs when an arrival refuses to enter a waiting line; a(n) occurs when an arrival joins a waiting line, then leaves it.