assignment 1b_nov 2013

8/13/2019 Assignment 1b_nov 2013

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FARAH HANIM BINTI ABDUL WAHID

2011522697

ACS1125A

ASSIGNMENT 1b

DUE DATE: 6/12/2013 (5pm)

Multiple Choice Questions

Question 1Two properties of random number tables areA) uniformity and randomnessB) normality and orderC) independence and normalityD) independence and uniformity

Question 2

Natural logarithms are used in simulatingA) binomial distributionB) negative exponential distributionC) normal distributionD) uniform distribution

Question 3Important benefits of simulation include

A) handling of problems that cannot be solved analyticallyB) always finding the optimal solutionC) relatively fast and cheap calculationsD) evaluating and finding an exact solution for the problem at hand

Question 4If you are interested in predicting the time of day a road block may occur, you would use

A) fixed interval simulationB) next event simulationC) deterministic simulationD) any one of A, B, or C can be used

Question 5Aspects of validation includeA) test of reasonablenessB) generating results similar to known systems

C) checking assumptions and values of parameters used in the modelD) all of the above


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Discussion and Review Questions

Question 1Explain what is meant by the term operations research

Operations research is the scientific approach to managerial decision making which involves the

application of mathematical method to develop a model and then to develop a solution. The

techniques have been applied successfully in many areas such as business, government,

health care, education and bank. Operations research also referred to as quantitative analysis,

quantitative method, management science and decision science.

Question 2Suppose you have just been hired by a small firm. After being on the job for a few weeks, you

realize that most problem solving is done on an informal basis; quantitative models are not

being used. You share your reservations about this with your manager, and after a certain

amount of discussion, your manager asks you to outline your reasoning on why the firm shouldadopt a more quantitative approach to problem solving. What would the main points of your

response be?

The first main point is quantitative approach can help a decision maker formulate problem. The

second main point is the quantitative approach is easy to conduct and calculate by using

computers and spreadsheet. The third main point is quantitative approach can save time and

money in decision making and problem solving.

Question 3

Suppose that senior management has asked you to give a presentation that will enlighten themon the use of models for problem solving. Specifically, they want to know what a model is, what

types of models there are, how models can lead to good solutions and any potential pitfalls to

be aware of. Outline your presentation.

Definition: Model is a representation (usually mathematical) of a situation.

Types of model: 1. Schematic modela picture, drawing or chart of reality

2. Mathematical modela set of mathematical relationships

3. Physical modeluse by architect to make building that they construct

4. Scale modeluse by engineer to develop chemical plant

Model can lead to good solutions by the following criteria:

1. The model should be developed carefully

2. The model should be solvable and realistic

3. The model should be easy to understand and modify

4. The model should contain at least one or more variable and parameters


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Potential pitfalls to be aware of:

1. The data is not obtain

2. Not enough amount of detail

Question 4You are faced with making a choice between two models. One is fairly simple model that willprovide an approximate answer to the problem; the other is a much more complex model thatcan be expected to provide a much more precise answer to the problem.

Under what circumstances would you choose the simple model?Simple model is use when all input variables are known and have constant value

Under what circumstances would the more sophisticated model be your choice?Sophisticated model is use when at least one input variables in uncertain

Question 5Briefly describe the operations research approach to problem solving.

The first step is defining the problem. The problem must be clear and concisely defined.Improperly defining a problem can easily result in no solution or an inappropriate solution. Thesecond step is developing a model. Model is a representation of a situation that may be iconic,analog and mathematical. Models contain variables and parameters. The third step is acquiringinput data. Obtaining accurate data for the model is essential. Data may come from companyreports, company documents and interviews. The fourth step is developing a solution. Thisinvolves in manipulating the model to arrive at the best solution to the problem. Solution must bepractical and implementable. The fifth step is testing the solution. The solution depends on theinput data and the model. The sixth step is analyzing the result. Analyzing the results starts with

determining the implications of the solution. The seventh step is implementing the results. Thisis the process of incorporating the solution into the company.

Question 6Contrast deterministic and probabilistic model, and indicate the conditions under which eachtype would be appropriate.

Deterministic model Probabilistic model

do not involve risk and chance involve risk and chance

have constant value the value are varies

for example, the EOQ model in inventorycontrol

for example, simulation model using MonteCarlo Method

condition: when all input variables are knownor certain

condition: at least one input variables isuncertain


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Question 7Suppose that after a considerable amount of time and effort, the solution obtained from a model

is not implemented.

List some possible reason for this.

1. The solution have wrong objective

2. The solution obtained not accurate3. The data is insufficient

Would you say that the time and effort was, therefore probably wasted? Explain your

answer

The time and effort is not wasted. This is because time and effort do not affect the

solution which will obtain from a model.

Question 8What does the phase modeling can become an end in itself mean? Is this necessarily bad?

The phase means that some of the model in operations research is too complex to handle. It is

bad because we will not get the answer to the problem.

Question 9Why might a solution that is optimal in a model not be optimal in reality? How might the gap be

closed? What risks might there be in attempting to close the gap?

A solution that is optimal in a model not be optimal in reality because a model can be measureby using assumptions which will produce different answer. The gap can be closed by choosing

the model based on past occurrence. The risk that might happen in attempting to close the gapis when the past occurrence might not happen in the future.

Question 10How and why are computers an integral part of operations research?

Computers are critical in stimulating complex tasks. They can generate random numbers,

simulate thousands of time periods in a matter of seconds or minutes and provide management

with reports that make decision making easier. By using POM-QM for windows and Excel QM

through computers, this allows us to solve problems and complicated mathematical calculation.

assignment 1b_nov 2013

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