Question 1

When a waiting system is in steady-state operation, the number of units in the system is not changing.

Accepted Answer

A) True 
 B)False  False

Question 2

In a multiple channel system

Accepted Answer

A) each server has its own queue. 
B) each server has the same service rate. 
C) $\mu$ > $\lambda$ 
D) All of the alternatives are correct. 
A) each server has its own queue. 
B) each server has the same service rate. 
C) $\mu$ > $\lambda$ 
D) All of the alternatives are correct. B

Question 3

Before waiting lines can be analyzed economically, the arrivals' cost of waiting must be estimated.

Accepted Answer

A) True 
 B)False  True

Question 4

Which of the following can NOT be found by the queuing formulas presented in the textbook?

Accepted Answer

A) the probability that no units are in the system. 
B) the average number of units in the system. 
C) the maximum time a unit spends in the system. 
D) the average time a unit spends in the system. 
A) the probability that no units are in the system. 
B) the average number of units in the system. 
C) the maximum time a unit spends in the system. 
D) the average time a unit spends in the system.

Question 5

In a multiple channel system it is more efficient to have a separate waiting line for each channel.

Accepted Answer

A) True 
 B)False

Question 6

Models with a finite calling population

Accepted Answer

A) have an arrival rate independent of the number of units in the system. 
B) have a service rate dependent on the number of units in the system. 
C) use the size of the population as a parameter in the operating characteristics formulas. 
D) All of the alternatives are correct. 
A) have an arrival rate independent of the number of units in the system. 
B) have a service rate dependent on the number of units in the system. 
C) use the size of the population as a parameter in the operating characteristics formulas. 
D) All of the alternatives are correct.

Question 7

Performance measures dealing with the number of units in line and the time spent waiting are called

Accepted Answer

A) queuing facts. 
B) performance queues. 
C) system measures. 
D) operating characteristics. 
A) queuing facts. 
B) performance queues. 
C) system measures. 
D) operating characteristics.

Question 8

Little's flow equations

Accepted Answer

A) require Poisson and exponential assumptions. 
B) are applicable to any waiting line model. 
C) require independent calculation of W, L, Wq, and Lq. 
D) All of the alternatives are correct. 
A) require Poisson and exponential assumptions. 
B) are applicable to any waiting line model. 
C) require independent calculation of W, L, Wq, and Lq. 
D) All of the alternatives are correct.

Question 9

In waiting line systems where the length of the waiting line is limited, the mean number of units entering the system might be less than the arrival rate.

Accepted Answer

A) True 
 B)False

Question 10

In a waiting line situation, arrivals occur, on average, every 10 minutes, and 10 units can be received every hour.What are $\lambda$ and $\mu$?

Accepted Answer

A) $\lambda$ = 10, $\mu$ = 10 
B) $\lambda$ = 6, $\mu$ = 6 
C) $\lambda$ = 6, $\mu$ = 10 
D) $\lambda$ = 10, $\mu$ = 6 
A) $\lambda$ = 10, $\mu$ = 10 
B) $\lambda$ = 6, $\mu$ = 6 
C) $\lambda$ = 6, $\mu$ = 10 
D) $\lambda$ = 10, $\mu$ = 6

Question 11

The manner in which units receive their service, such as FCFS, is the

Accepted Answer

A) queue discipline. 
B) channel. 
C) steady state. 
D) operating characteristic. 
A) queue discipline. 
B) channel. 
C) steady state. 
D) operating characteristic.

Question 12

Queue discipline refers to the manner in which waiting units are arranged for service.

Accepted Answer

A) True 
 B)False

Question 13

The total cost for a waiting line does NOT specifically depend on

Accepted Answer

A) the cost of waiting. 
B) the cost of service. 
C) the number of units in the system. 
D) the cost of a lost customer. 
A) the cost of waiting. 
B) the cost of service. 
C) the number of units in the system. 
D) the cost of a lost customer.

Question 14

Operating characteristics formulas for the single-channel queue do NOT require

Accepted Answer

A) $\lambda$ > $\mu$. 
B) Poisson distribution of arrivals. 
C) an exponential distribution of service times. 
D) an FCFS queue discipline. 
A) $\lambda$ > $\mu$. 
B) Poisson distribution of arrivals. 
C) an exponential distribution of service times. 
D) an FCFS queue discipline.

Question 15

The assumption of exponentially distributed service times indicates that

Accepted Answer

A) 37% of the service times are less than the mean service time. 
B) 50% of the service times are less than the mean service time. 
C) 63% of the service times are less than the mean service time. 
D) service time increase at an exponential rate as the waiting line grows. 
A) 37% of the service times are less than the mean service time. 
B) 50% of the service times are less than the mean service time. 
C) 63% of the service times are less than the mean service time. 
D) service time increase at an exponential rate as the waiting line grows.

Question 16

Use of the Poisson probability distribution assumes that arrivals are not random.

Accepted Answer

A) True 
 B)False

Question 17

Decision makers in queuing situations attempt to balance

Accepted Answer

A) operating characteristics against the arrival rate. 
B) service levels against service cost. 
C) the number of units in the system against the time in the system. 
D) the service rate against the arrival rate. 
A) operating characteristics against the arrival rate. 
B) service levels against service cost. 
C) the number of units in the system against the time in the system. 
D) the service rate against the arrival rate.

Question 18

If some maximum number of customers is allowed in a queuing system at one time, the system has a finite calling population.

Accepted Answer

A) True 
 B)False

Question 19

If arrivals occur according to the Poisson distribution every 20 minutes, then which is NOT true?

Accepted Answer

A) $\lambda$ = 20 arrivals per hour 
B) $\lambda$ = 3 arrivals per hour 
C) $\lambda$ = 1/20 arrivals per minute 
D) $\lambda$ = 72 arrivals per day 
A) $\lambda$ = 20 arrivals per hour 
B) $\lambda$ = 3 arrivals per hour 
C) $\lambda$ = 1/20 arrivals per minute 
D) $\lambda$ = 72 arrivals per day

Question 20

When blocked customers are cleared, an important decision is how many channels to provide.

Accepted Answer

A) True 
 B)False

Exam 11: Waiting Line Models

When a waiting system is in steady-state operation, the number of units in the system is not changing.

In a multiple channel system

Before waiting lines can be analyzed economically, the arrivals' cost of waiting must be estimated.

Which of the following can NOT be found by the queuing formulas presented in the textbook?

In a multiple channel system it is more efficient to have a separate waiting line for each channel.

Models with a finite calling population

Performance measures dealing with the number of units in line and the time spent waiting are called

Little's flow equations

In waiting line systems where the length of the waiting line is limited, the mean number of units entering the system might be less than the arrival rate.

In a waiting line situation, arrivals occur, on average, every 10 minutes, and 10 units can be received every hour.What are λ\lambdaλ and μ\muμ ?

The manner in which units receive their service, such as FCFS, is the

Queue discipline refers to the manner in which waiting units are arranged for service.

The total cost for a waiting line does NOT specifically depend on

Operating characteristics formulas for the single-channel queue do NOT require

The assumption of exponentially distributed service times indicates that

Use of the Poisson probability distribution assumes that arrivals are not random.

Decision makers in queuing situations attempt to balance

If some maximum number of customers is allowed in a queuing system at one time, the system has a finite calling population.

If arrivals occur according to the Poisson distribution every 20 minutes, then which is NOT true?

When blocked customers are cleared, an important decision is how many channels to provide.

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In a waiting line situation, arrivals occur, on average, every 10 minutes, and 10 units can be received every hour.What are $\lambda$ and $\mu$ ?