Question 1

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 2

A waiting line model meeting the assumptions of M/M/1 has an arrival rate of 2 per hour and a service rate of 6 per hour.What is the utilization factor for the system?

Accepted Answer

A) 0.25 
B) 0.33 
C) 0.50 
D) 0.67 
E) 3.00 
A) 0.25 
B) 0.33 
C) 0.50 
D) 0.67 
E) 3.00

Question 3

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 4

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 5

A finite population waiting line model with N = 5 has an average arrival rate of 1/2 customer per hour and a mean service rate of 5 customers per hour.What is the probability the system is empty?

Accepted Answer

A) 5.64 
B) 0.56 
C) 0.056 
D) .2 
E) 1.00 
A) 5.64 
B) 0.56 
C) 0.056 
D) .2 
E) 1.00

Question 6

The common measures of a queuing system's performance include:

Accepted Answer

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

Question 7

A waiting line or ________ is where items or people are in a line awaiting service;________ is a body of knowledge about waiting lines.

Accepted Answer

queue,queu

Question 8

The potential restaurant customer who says to her husband,"The line looks too long;let's eat somewhere else," is an illustration of which element of arrival behavior?

Accepted Answer

A) first-in,first-out 
B) balk 
C) renege 
D) random departure 
E) frustration 
A) first-in,first-out 
B) balk 
C) renege 
D) random departure 
E) frustration

Question 9

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 10

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.What is the average number of units waiting in the queue?

Accepted Answer

A) approximately 0.1603 
B) approximately 0.4103 
C) approximately 0.8013 
D) approximately 1.0417 
E) Cannot be calculated because λ is larger than μ. 
A) approximately 0.1603 
B) approximately 0.4103 
C) approximately 0.8013 
D) approximately 1.0417 
E) Cannot be calculated because λ is larger than μ.

Question 11

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

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 12

What are Ls and Lq,as used in waiting line terminology? Which is larger,Ls or Lq? Explain.

Accepted Answer

Ls is the average number of units in the

Question 13

In the basic queuing model (M/M/1),what probability distribution describes service times?

Accepted Answer

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

Question 14

A finite population waiting line model (D)differs from the single service model (A)in that:

Accepted Answer

A) it has more than one server. 
B) the average length of the queue is less than 5. 
C) customers are served first-come,first-served. 
D) arrivals are Poisson distributed. 
E) the population of people or units seeking service is finite. 
A) it has more than one server. 
B) the average length of the queue is less than 5. 
C) customers are served first-come,first-served. 
D) arrivals are Poisson distributed. 
E) the population of people or units seeking service is finite.

Question 15

Which part of a waiting line has characteristics that involve a statistical distribution?

Accepted Answer

A) arrivals or inputs 
B) the waiting line itself 
C) the service facility 
D) A and C 
E) A,B,and C 
A) arrivals or inputs 
B) the waiting line itself 
C) the service facility 
D) A and C 
E) A,B,and C

Question 16

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 Finite population or D-all share three characteristics: Poisson arrivals,FIFO discipline,and exponential service times.

Accepted Answer

A) True 
 B)False

Question 17

The ________ probability distribution is a continuous probability distribution often used to describe the service time in a queuing system.

Accepted Answer

negative e

Question 18

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

Accepted Answer

A) True 
 B)False

Question 19

The source population is considered to be either ________ in its size.

Accepted Answer

A) finite or infinite 
B) fixed or variable 
C) known or unknown 
D) random or scheduled 
E) small or large 
A) finite or infinite 
B) fixed or variable 
C) known or unknown 
D) random or scheduled 
E) small or large

Question 20

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

Exam 25: Waiting-Line Models

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

A waiting line model meeting the assumptions of M/M/1 has an arrival rate of 2 per hour and a service rate of 6 per hour.What is the utilization factor for the system?

A finite population waiting line model with N = 5 has an average arrival rate of 1/2 customer per hour and a mean service rate of 5 customers per hour.What is the probability the system is empty?

The common measures of a queuing system's performance include:

A waiting line or ________ is where items or people are in a line awaiting service;________ is a body of knowledge about waiting lines.

The potential restaurant customer who says to her husband,"The line looks too long;let's eat somewhere else," is an illustration of which element of arrival behavior?

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?

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.What is the average number of units waiting in the queue?

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

What are Ls and Lq,as used in waiting line terminology? Which is larger,Ls or Lq? Explain.

In the basic queuing model (M/M/1),what probability distribution describes service times?

A finite population waiting line model (D)differs from the single service model (A)in that:

Which part of a waiting line has characteristics that involve a statistical 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 Finite population or D-all share three characteristics: Poisson arrivals,FIFO discipline,and exponential service times.

The ________ probability distribution is a continuous probability distribution often used to describe the service time in a queuing system.

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

The source population is considered to be either ________ in its size.

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

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A waiting line or is where items or people are in a line awaiting service; is a body of knowledge about waiting lines.