Deck 22: Supplement E Simulation

Question 1

The manager of a branch bank wants to build a simulation model of the lobby operation to reduce the waiting time of her customers. The number of tellers is an example of:

A) a decision variable.
B) an uncontrollable variable.
C) a time-compressed variable.
D) a dependent variable.

Answer 1

A

Question 2

The manager of a branch bank wants to build a simulation model of the lobby operation to reduce the waiting time of her customers. The number of customers waiting in line at any point of time is an example of a(n):

A) decision variable.
B) dependent variable.
C) uncontrollable variable.
D) time-compressed variable.

Answer 2

B

Question 3

Any random number has the same likelihood of being selected as any other, regardless of how recently it has been selected.

Answer 3

True

Question 4

Using a simulation model to gather a year of operating data in a few minutes is known as:

A) historical search data collection.
B) Monte Carlo optimization.
C) sub-optimization.
D) time compression.

Question 5

What are the motivations for using simulation for analyzing processes?

Question 6

Random variables are under the control of the decision maker.

Question 7

A manager has been given the table shown below and is asked to generate random numbers. Which of the following statements is True?

A) There are no customers in the store 49 percent of the time.
B) The probability of having one customer in the store is 0.30.
C) The relative frequency of having two customers in the store is 0.80.
D) If we randomly choose the numbers 0 through 99 enough times, about 99 percent of the time we will have two customers in the store.

Question 8

What are the differences between decision variables and uncontrolled variables? Describe the differences and provide an example from a simulation model.

Question 9

Which one of the following relationships is correct?

A) Decision variables reflect the value of uncontrollable variables.
B) Dependent variables reflect the value of decision and uncontrollable variables.
C) Uncontrollable variables reflect the value of decision variables.
D) Uncontrollable variables reflect the values of dependent variables.

Question 10

Which one of the following statements regarding simulation analysis is False?

A) Simulation analysis is a form of hypothesis testing.
B) In simulation, dependent variables reflect the values of both the decision variables and the uncontrollable variables.
C) Statistical methods require the replication of simulation runs.
D) Each time a simulation model is run for a given set of decision variables, the same random numbers must be used.

Question 11

Simulation models are:

A) useful when waiting line models are too complex.
B) useful for conducting experiments using the real system.
C) preferred because they find optimal solutions.
D) usually inexpensive relative to other approaches.

Question 12

A simulation model:

A) describes operating characteristics with known equations.
B) replicates the service of customers and keeps track of characteristics such as the number in line, the waiting time, and the total time in the system.
C) prescribes what should be done in a situation.
D) finds the optimal solution to a problem without having to try each alternative.

Question 13

The manager of a branch bank wants to build a simulation model of the lobby operation to reduce the waiting time of her customers. The number of customers arriving at any point of time is an example of a(n):

A) decision variable.
B) uncontrollable variable.
C) time-compressed variable.
D) dependent variable.

Question 14

What is the difference between a waiting line model as described in Supplement B and a simulation model of a waiting line problem?

Question 15

Time compression is the feature of simulation that allows managers to obtain operating-characteristic estimates in much less time than is required to gather the same operating data from a real system.

Question 16

________ is the act of reproducing the behavior of a system using a model that describes the processes of the system.

Question 17

Monte Carlo simulation is the use of computer graphics to show customers or products moving through a series of process steps.

Question 18

What is meant by time compression in a simulation model?

Question 19

Simulation is the process of reproducing the behavior of a system using a model that describes the processes of the system.

Question 20

________ is a feature of simulation models that allows them to obtain operating-characteristic estimates in much less time than is required to gather the same operating data from a real system.

Question 21

How can random numbers be generated?

Question 22

In Excel, the RAND() function generates either a 0 or a 1, purely at random.

Question 23

A number that has the same probability of being selected as any other number is a(n) ________.

Question 24

To generate 100 random numbers in an Excel simulation, the "=RAND()" function is first typed into the A1 cell on an Excel spreadsheet. A1 can then be copied and pasted in a rectangular area on the spreadsheet to cover the cells:

A) A1:E5.
B) A1:H12.
C) A1:J10.
D) A1:E22.

Question 25

________ occurs when the simulation is repeated over enough time that the average results for performance measures remain constant.

Question 26

________ are random events that the decision maker cannot control.

Question 27

One hundred monkeys are typing in Excel spreadsheets when one of them enters =NORM.S.INV(RAND()) What is the result of this monkey's function?

A) the number zero
B) random numbers evenly distributed from 0 to 1 inclusive
C) probabilities of the normal distribution function
D) z-scores from the standard normal distribution

Question 28

A simulation model is used to test the impact of the number of sample customers at a supermarket. As the model is run, the decision maker watches the average number of customers in the store rapidly increase from zero until it levels off and holds a constant value. The simulation model is:

A) not valid due to the lack of change.
B) in steady state.
C) not valid due to the fluctuation in the statistics.
D) a random variable.

Question 29

A variable that is controlled by the decision-maker and will change from one run to the next as different events are simulated is a(n) ________.

Question 30

When using Excel for simulation, it is important to freeze the random numbers used in order to compare the effectiveness of different policies. To do this, you must select the cells holding the random numbers with the mouse, click Edit/Copy at the top of the spreadsheet, and:

A) click Edit/Paste Special and select the Values option.
B) click Edit/Paste to freeze the cells.
C) click Edit/Paste Special and select the Formulas option.
D) move to a different section of the spreadsheet, then click Edit/Paste to freeze the cells.

Question 31

This table shows the distribution of grades in an operations management class.
Add a column to the table that shows the cumulative probability and indicate what letter grade is obtained when the RAND() function is equal to 0.5548.

A) A
B) B
C) C
D) D

Question 32

________ uses random numbers to generate simulation events.

Question 33

To generate 80 random numbers in an Excel simulation, the "=RAND()" function is first typed into the C2 cell on an Excel spreadsheet. C2 is then copied and pasted in a rectangular area on the spreadsheet to cover the cells:

A) C2:G13.
B) C2:J11.
C) C2:F20.
D) C2:D40.

Question 34

This table shows the distribution of grades in an operations management class.
Add a column to the table that shows the cumulative probability and indicate what letter grade is obtained when the RAND() function is equal to 0.982245.

A) A
B) B
C) C
D) F

Question 35

If the difference in results between different simulation runs results in a mathematical difference in system performance, the difference is said to be ________.

Question 36

In Excel, typing the function ________ will generate random numbers within the interval 0 to 1.

Question 37

Why would data need to be collected prior to conducting a simulation?

Question 38

If the data needed to set up a simulation are available in company records, the technique used to obtain them is called ________.

Question 39

This table shows the distribution of grades in an operations management class.
Add a column to the table that shows the cumulative probability and indicate what letter grade is obtained when the RAND() function is equal to 0.7406.

A) A
B) B
C) C
D) D

Question 40

Steady state occurs when the simulation is repeated over enough time that the average results for performance measures remain constant.

Question 41

Scenario E.1
SimQuick is being used to simulate the following bank process:

Customer arrivals at the Entrance Door of the bank with an average time between arrivals of 2.5 minutes. The Line Buffer holds 6 customers. If a customer arrives and the buffer line is filled, the customer leaves. The Work Station Teller's processing time per customer is normally distributed, with a mean of 3.0 minutes and a standard deviation of 0.5 minutes. The Served Customer Buffer in the flow chart is used to count the number of customers processed during the period simulated. A 2-hour period was simulated.
The SimQuick simulation is run, and the results are as follows:

Use the information in Scenario E.1. Approximately how many total customers arrived during the 2-hour period simulated?

A) 42
B) 38
C) 44
D) 48

Question 42

Refer to the bank process model. The bank's process improvement group has developed a number of process and technology changes that will improve the Teller's process rate per customer from a mean of 3.0 minutes to 2.5 minutes (standard deviation remains at 0.5 minutes). The Bank Manager wants to determine if the improved process rate, along with the special promotion for new customers, will allow the "arrive and immediately leave" rate and average customer wait time in line achieved to still be met (12% balk rate, 9.95 minutes in line). If so, the manager will implement the process and technology changes and allow the special promotion to proceed. Using SimQuick, estimate the new arrive and immediately leave rate and average time in line. What decision should the manager make?

Question 43

A patient's interminable wait for the first available physician is modeled in SimQuick using a(n):

A) entrance block.
B) buffer block.
C) workstation block.
D) decision point.

Question 44

Refer to the bank process model. The Marketing Department for the bank has decided to run a special promotion for new customers that will increase the number of customers arriving at the bank. The new arrival rate is expected to be an average time between arrivals of 2.0 minutes instead of the current average time between arrivals of 2.5 minutes. With the potential increase in business, the bank manager is concerned about the number of customers who will arrive and leave because the line is full (with 6 customers) and the average wait time in line at the bank. All other parameters of the model remain the same. Using SimQuick, estimate the new arrive and immediately leave rate and average time in line. Should the manager be concerned?

Question 45

What is steady state in a simulation model? Why is it important to achieve steady state?

Question 46

Scenario E.1
SimQuick is being used to simulate the following bank process:

Customer arrivals at the Entrance Door of the bank with an average time between arrivals of 2.5 minutes. The Line Buffer holds 6 customers. If a customer arrives and the buffer line is filled, the customer leaves. The Work Station Teller's processing time per customer is normally distributed, with a mean of 3.0 minutes and a standard deviation of 0.5 minutes. The Served Customer Buffer in the flow chart is used to count the number of customers processed during the period simulated. A 2-hour period was simulated.
The SimQuick simulation is run, and the results are as follows:

Use the information in Scenario E.1. Approximately what percentage of total customers who arrived during the 2-hour period found the buffer full and were not able to enter?

A) 87%
B) 13%
C) 94%
D) 6%

Question 47

SimQuick is to be used to simulate the following bank process:

Customers arrive at the Entrance Door of the bank with an average time between arrivals of 2.5 minutes. The Line Buffer holds 6 customers. If a customer arrives and the buffer line is filled, the customer leaves. The Work Station Teller's processing time per customer is normally distributed, with a mean of 3.0 minutes and a standard deviation of 0.5 minutes. The Served Customer Buffer in the flowchart is used to count the number of customers processed during the simulation period. A 2-hour period is to be simulated and the simulation should be repeated 30 times. Determine:
a) The number of customers served during the 2-hour period;
b) The percentage of customers who arrived at the bank and left because the buffer line was full;
c) The utilization of the teller (% of time working) during the 2-hour period;

Question 48

Which of the following statements about SimQuick is True?

A) SimQuick requires some knowledge of programming languages, such as VISUAL BASIC or C++.
B) SimQuick can be used to simulate the flow of materials, but cannot be used to study the process flows that involve people or information.
C) SimQuick is an easy-to-use package that is simply an Excel spreadsheet with some macros.
D) The primary disadvantage of SimQuick is that it is more costly and more difficult to set up when compared to other models, such as SIMPROCESS and ProModel.

Question 49

Scenario E.1
SimQuick is being used to simulate the following bank process:

Customer arrivals at the Entrance Door of the bank with an average time between arrivals of 2.5 minutes. The Line Buffer holds 6 customers. If a customer arrives and the buffer line is filled, the customer leaves. The Work Station Teller's processing time per customer is normally distributed, with a mean of 3.0 minutes and a standard deviation of 0.5 minutes. The Served Customer Buffer in the flow chart is used to count the number of customers processed during the period simulated. A 2-hour period was simulated.
The SimQuick simulation is run, and the results are as follows:

Use the information in Scenario E.1. Approximately how much time did the average customer who entered the system spend waiting in line?

A) 9.75 minutes
B) 3.08 minutes
C) 5.85 minutes
D) 3.98 minutes

Question 50

The arrival of customers at a lemonade stand is modeled in SimQuick using a(n):

A) entrance block.
B) buffer block.
C) workstation block.
D) decision point.

Question 51

SimQuick can be used to simulate all of the following except:

A) a call center with completely random call arrivals and processing times.
B) a hospital emergency room with arrivals that vary during different time periods throughout the day.
C) a manufacturing process with a constant arrival rate (e.g., every 2 minutes) at one of the process steps.
D) the hiring of production workers, based on skill requirements throughout the year.

Question 52

Describe a general procedure for generating normally distributed random numbers with a mean of 450 and standard deviation of 50 using Excel functions.

Question 53

Big Bills McGee does not carry any paper money in his wallet that has a denomination less than $10, preferring to have a ready supply of $10, $20, $50, and $100 denominations at all times. He is concerned about pickpockets and has an amusing anecdote about thwarting a pickpocket on the Athens subway he likes to tell. His business associate conducts a Monte Carlo simulation for Big Bills using POM for Windows software and prints out the results copied below. Using this output, provide your interpretation for Big Bills pickpocket scenario.

Question 54

Scenario E.1
SimQuick is being used to simulate the following bank process:

Customer arrivals at the Entrance Door of the bank with an average time between arrivals of 2.5 minutes. The Line Buffer holds 6 customers. If a customer arrives and the buffer line is filled, the customer leaves. The Work Station Teller's processing time per customer is normally distributed, with a mean of 3.0 minutes and a standard deviation of 0.5 minutes. The Served Customer Buffer in the flow chart is used to count the number of customers processed during the period simulated. A 2-hour period was simulated.
The SimQuick simulation is run, and the results are as follows:

Use the information in Scenario E.1. On average, approximately how many customers were waiting in line during the 2-hour simulation period?

A) 5
B) 4
C) 3
D) 2