ISYE 6644 Exam 2 Study Notes: 300 Questions
and Answers with Rationales (100
Correct/Verified/Latest Update 2026/2027)
1. Which statement best describes discrete-event simulation (DES)?
A. It models only continuous physical processes.
B. It represents system evolution as a sequence of events occurring at
discrete points in time.
C. It assumes all system variables remain constant.
D. It eliminates the need for probability distributions.
Answer: B
Rationale: In DES, the system state changes when events occur—for
example, an arrival to a queue or completion of service. Time advances
from one event occurrence to the next rather than necessarily being
evaluated continuously.
2. A simulation model of a bank includes customer arrivals, waiting
lines, tellers, and service times. Which of the following is an example
of an entity?
A. Teller
B. Queue length
C. Customer
D. Service-time distribution
,Answer: C
Rationale: An entity is an object that flows through the simulated
system. Here, customers enter the bank, wait, receive service, and
depart. A teller is typically a resource, while queue length is a system-
state measure.
3. In a discrete-event simulation, what is the simulation clock?
A. The computer's actual clock
B. The number of replications completed
C. A variable representing simulated time
D. The average service time
Answer: C
Rationale: The simulation clock records the current time within the
modeled system. It advances as events are processed and does not
necessarily correspond to real-world elapsed computer time.
4. Which event would normally cause a queueing system's state to
change?
A. Customer arrival
B. Printing the simulation report
C. Saving the model file
D. Changing the computer's screen resolution
Answer: A
Rationale: A customer arrival changes the number of entities in the
system and may cause a queue to form or a resource to become
occupied. Such state-changing occurrences are simulation events.
,5. What is the primary purpose of a conceptual model?
A. To specify the computer's hardware requirements
B. To describe the system, assumptions, entities, resources, processes,
and relationships before implementation
C. To calculate the final confidence interval automatically
D. To eliminate randomness from the simulation
Answer: B
Rationale: Conceptual modeling establishes what the simulation should
represent and what assumptions will be made. It provides the foundation
for translating the real system into a computational model.
6. Which situation is most appropriate for simulation?
A. A simple algebraic equation with an exact closed-form solution
B. A complex stochastic system involving queues and interacting
resources
C. A problem requiring no uncertainty or variability
D. A calculation that can be solved instantly with arithmetic
Answer: B
Rationale: Simulation is particularly useful when systems are complex,
stochastic, dynamic, or difficult to analyze mathematically. Queueing
systems with multiple interacting processes are common examples.
7. What is verification primarily concerned with?
A. Whether the model represents reality accurately
B. Whether the computer code/model was implemented correctly
, C. Whether the input data are normally distributed
D. Whether the system should be simulated
Answer: B
Rationale: Verification asks, “Did we build the model right?” It
focuses on implementation and logical correctness. Validation asks
whether the model adequately represents the real-world system.
8. What is validation primarily concerned with?
A. Checking syntax errors in the model
B. Determining whether the simulation adequately represents the real
system for its intended purpose
C. Checking whether random numbers are stored correctly
D. Determining the computer's processing speed
Answer: B
Rationale: Validation compares the model's behavior and outputs with
the real system or accepted knowledge about it. A model can be
correctly programmed yet still fail to represent the intended system.
9. Why are random numbers important in stochastic simulation?
A. They make every replication identical.
B. They represent variability and uncertainty in modeled processes.
C. They eliminate sampling error.
D. They guarantee exact predictions.
Answer: B
Rationale: Random numbers are transformed into random observations
from specified probability distributions. They allow simulation models
and Answers with Rationales (100
Correct/Verified/Latest Update 2026/2027)
1. Which statement best describes discrete-event simulation (DES)?
A. It models only continuous physical processes.
B. It represents system evolution as a sequence of events occurring at
discrete points in time.
C. It assumes all system variables remain constant.
D. It eliminates the need for probability distributions.
Answer: B
Rationale: In DES, the system state changes when events occur—for
example, an arrival to a queue or completion of service. Time advances
from one event occurrence to the next rather than necessarily being
evaluated continuously.
2. A simulation model of a bank includes customer arrivals, waiting
lines, tellers, and service times. Which of the following is an example
of an entity?
A. Teller
B. Queue length
C. Customer
D. Service-time distribution
,Answer: C
Rationale: An entity is an object that flows through the simulated
system. Here, customers enter the bank, wait, receive service, and
depart. A teller is typically a resource, while queue length is a system-
state measure.
3. In a discrete-event simulation, what is the simulation clock?
A. The computer's actual clock
B. The number of replications completed
C. A variable representing simulated time
D. The average service time
Answer: C
Rationale: The simulation clock records the current time within the
modeled system. It advances as events are processed and does not
necessarily correspond to real-world elapsed computer time.
4. Which event would normally cause a queueing system's state to
change?
A. Customer arrival
B. Printing the simulation report
C. Saving the model file
D. Changing the computer's screen resolution
Answer: A
Rationale: A customer arrival changes the number of entities in the
system and may cause a queue to form or a resource to become
occupied. Such state-changing occurrences are simulation events.
,5. What is the primary purpose of a conceptual model?
A. To specify the computer's hardware requirements
B. To describe the system, assumptions, entities, resources, processes,
and relationships before implementation
C. To calculate the final confidence interval automatically
D. To eliminate randomness from the simulation
Answer: B
Rationale: Conceptual modeling establishes what the simulation should
represent and what assumptions will be made. It provides the foundation
for translating the real system into a computational model.
6. Which situation is most appropriate for simulation?
A. A simple algebraic equation with an exact closed-form solution
B. A complex stochastic system involving queues and interacting
resources
C. A problem requiring no uncertainty or variability
D. A calculation that can be solved instantly with arithmetic
Answer: B
Rationale: Simulation is particularly useful when systems are complex,
stochastic, dynamic, or difficult to analyze mathematically. Queueing
systems with multiple interacting processes are common examples.
7. What is verification primarily concerned with?
A. Whether the model represents reality accurately
B. Whether the computer code/model was implemented correctly
, C. Whether the input data are normally distributed
D. Whether the system should be simulated
Answer: B
Rationale: Verification asks, “Did we build the model right?” It
focuses on implementation and logical correctness. Validation asks
whether the model adequately represents the real-world system.
8. What is validation primarily concerned with?
A. Checking syntax errors in the model
B. Determining whether the simulation adequately represents the real
system for its intended purpose
C. Checking whether random numbers are stored correctly
D. Determining the computer's processing speed
Answer: B
Rationale: Validation compares the model's behavior and outputs with
the real system or accepted knowledge about it. A model can be
correctly programmed yet still fail to represent the intended system.
9. Why are random numbers important in stochastic simulation?
A. They make every replication identical.
B. They represent variability and uncertainty in modeled processes.
C. They eliminate sampling error.
D. They guarantee exact predictions.
Answer: B
Rationale: Random numbers are transformed into random observations
from specified probability distributions. They allow simulation models
