ARE 155 – Spring 2010
Final Exam Review – Selected End-of-Chapter Answers
Note:
These are good questions to review for the short answer and multiple-choice questions.
CHAPTER 1
1-2.
Deterministic
models assume that all the relevant input data are known with certainty. That is, these
models assume that all the information needed for modeling the decision-making problem environment is
available, with fixed and known values. Students should be able to find several examples from the
manufacturing and service sectors. For example, deciding how many sections of a course to offer during a
semester can be modeled as a deterministic model since the costs and benefits of offering each section are
known.
Probabilistic
(also called
stochastic
) models assume that some input data are not known with
certainty. That is, these models assume that the values of some important variables will not be known
before
decisions are made. Here again, students should be able to find several examples from the
manufacturing and service sectors. For example, their own career based on their choice of a major for
their undergraduate study can be modeled as a probabilistic model.
1-3.
Quantitative factors are typically identifiable and measurable, making their inclusion in the model
relatively easy. In contrast, qualitative factors measure such things as perceptions, feelings, and opinions.
Although some qualitative factors do have scales of measures (for example, we can classify opinions of
the President’s performance as good, fair, or poor), in general, they are difficult to quantify and measure.
1-10.
A decision variable is an unknown quantity whose value can be controlled by the decision maker.
Examples include how many inventory items to order, how many courses to take this semester, how much
money to invest in retirement plans this year, etc.
1-11.
A problem parameter is a measurable (usually known) quantity that is inherent in the problem.
Examples include the cost of placing an order for more inventory items, the tuition payable for taking a
course, the annual fees payable for establishing a retirement plan, etc.
CHAPTER 2
SOLUTIONS TO DISCUSSION QUESTIONS
2-1.
The requirements for an LP problem are listed in Section 2.2. It is also assumed that conditions of
certainty
exist; that is, coefficients in the objective function and constraints are known with certainty and
do not change during the period being studied. Another basic assumption that mathematically
sophisticated students should be made aware of is
proportionality
in the objective function and
constraints. For example, if one product uses 5 hours of a machine resource, then making 10 of that
product uses 50 hours of machine time.
LP also assumes