Question 1

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 2

Which of the following is a measure of queue performance?

Accepted Answer

A) utilization factor for the system 
B) average queue length 
C) probability of a specific number of customers in the system 
D) average waiting time in the line 
E) all of the above 
A) utilization factor for the system 
B) average queue length 
C) probability of a specific number of customers in the system 
D) average waiting time in the line 
E) all of the above

Question 3

Which of the following is a requirement for application of Little's Law to be valid?

Accepted Answer

A) arrival rates that follow the Poisson distribution 
B) FIFO queue discipline 
C) steady state conditions 
D) single-server system 
E) multiphase system 
A) arrival rates that follow the Poisson distribution 
B) FIFO queue discipline 
C) steady state conditions 
D) single-server system 
E) multiphase system

Question 4

A waiting line,or queuing,system has three parts,which are:

Accepted Answer

A) distribution of arrival times,discipline while waiting,and distribution of service times. 
B) arrival rate,service rate,and utilization rate. 
C) arrival discipline,queue discipline,and service sequencing. 
D) arrivals or inputs,queue discipline or the waiting line itself,and the service facility. 
E) sequencing policy,penalty for reneging,and expediting of arrivals. 
A) distribution of arrival times,discipline while waiting,and distribution of service times. 
B) arrival rate,service rate,and utilization rate. 
C) arrival discipline,queue discipline,and service sequencing. 
D) arrivals or inputs,queue discipline or the waiting line itself,and the service facility. 
E) sequencing policy,penalty for reneging,and expediting of arrivals.

Question 5

The greater the margin by which the arrival rate exceeds the service rate,the better the performance of the waiting line.

Accepted Answer

A) True 
 B)False

Question 6

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 7

Suppose that 1 customer arrives each minute in a Poisson distribution.Is it more likely that 2 customers or 0 customers will arrive each minute?

Accepted Answer

P(0)= e^(-1)(1^0)/0! = .368
P(

Question 8

A dental clinic at which only one dentist works is open only two days a week.During those two days,patients arrive 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 and staff)?
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 9

Balk and renege are elements of queue discipline.

Accepted Answer

A) True 
 B)False

Question 10

A McDonald's single-lane drive-through that has one window for making the payment and a second window for receiving the food behaves most like 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) single-server,sequential-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) single-server,sequential-phase system

Question 11

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

Accepted Answer

A) True 
 B)False

Question 12

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

Question 13

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 before being served.

Accepted Answer

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

Question 14

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 mach

Question 15

A waiting-line system that meets the assumptions of M/M/1 has λ = 1,μ = 4.For this system,what is the probability of more than two units in the system?

Accepted Answer

A) zero 
B) 0.015625 
C) 0.0625 
D) 0.25 
E) 0.9375 
A) zero 
B) 0.015625 
C) 0.0625 
D) 0.25 
E) 0.9375

Question 16

Service times in an automobile repair shop tend to follow which probability distribution?

Accepted Answer

A) exponential 
B) normal 
C) triangular 
D) binomial 
E) Erlang 
A) exponential 
B) normal 
C) triangular 
D) binomial 
E) Erlang

Question 17

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).Which is cheaper,the existing system with one service crew,or a revised system with two service crews?

Accepted Answer

Ls for the single server is 8 / (11 - 8)

Question 18

Four of the most widely used waiting line models-M/M/1 or A,M/M/S or B,M/D/1 or C,and Limited population or D-all share which of the following three characteristics?

Accepted Answer

A) normal arrivals,FIFO discipline,and normal service times 
B) Poisson arrivals,FIFO discipline,and a single-service phase 
C) Poisson arrivals,FIFO discipline,and exponential service times 
D) Poisson arrivals,no queue discipline,and exponential service times 
E) Poisson arrivals,single-server,and FIFO discipline 
A) normal arrivals,FIFO discipline,and normal service times 
B) Poisson arrivals,FIFO discipline,and a single-service phase 
C) Poisson arrivals,FIFO discipline,and exponential service times 
D) Poisson arrivals,no queue discipline,and exponential service times 
E) Poisson arrivals,single-server,and FIFO discipline

Question 19

Which of the following occurs as the level of service decreases?

Accepted Answer

A) Cost of waiting time decreases,and cost of providing service decreases. 
B) Cost of waiting time decreases,and cost of providing service increases. 
C) Cost of waiting time increases,and cost of providing service decreases. 
D) Cost of waiting time increases,and cost of providing service increases. 
E) Cost of waiting time first decreases,then increases;while cost of providing service decreases. 
A) Cost of waiting time decreases,and cost of providing service decreases. 
B) Cost of waiting time decreases,and cost of providing service increases. 
C) Cost of waiting time increases,and cost of providing service decreases. 
D) Cost of waiting time increases,and cost of providing service increases. 
E) Cost of waiting time first decreases,then increases;while cost of providing service decreases.

Question 20

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.What is the average number in the system Ls in units?

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

Exam 25: Queuing Models

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.

Which of the following is a measure of queue performance?

Which of the following is a requirement for application of Little's Law to be valid?

A waiting line,or queuing,system has three parts,which are:

The greater the margin by which the arrival rate exceeds the service rate,the better the performance of the waiting line.

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

Suppose that 1 customer arrives each minute in a Poisson distribution.Is it more likely that 2 customers or 0 customers will arrive each minute?

Balk and renege are elements of queue discipline.

A McDonald's single-lane drive-through that has one window for making the payment and a second window for receiving the food behaves most like which of the following?

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

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 ________.

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 before being served.

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?

A waiting-line system that meets the assumptions of M/M/1 has λ = 1,μ = 4.For this system,what is the probability of more than two units in the system?

Service times in an automobile repair shop tend to follow which probability distribution?

Four of the most widely used waiting line models-M/M/1 or A,M/M/S or B,M/D/1 or C,and Limited population or D-all share which of the following three characteristics?

Which of the following occurs as the level of service decreases?

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.What is the average number in the system Ls in units?

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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 .

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 before being served.