SCM 564 Midterm

Decision variables limit the degree to which the objective in a linear programming problem is satisfied T/F

False

a variable with a final value equal to its simple lower or upper bound and a reduced cost of zero indicates that a. an alternate optimal solution exists b. an error in formulation has been made c. the right hand sides should be increased d. the objective function needs new coefficients

a. an alternate optimal solution exists

a production optimization problem has 4 decision variables and a requirement that at least b1 units of material 1 are consumed. Which of the following constraints reflects this fact? a. f(X1, X2, X3, X4) <= b1 b. f(X1, X2, X3, X4) >= b1 c. f(X1, X2, X3, X4) = b1 d. f(X1, X2, X3, X4) /= b1

b. f(X1, X2, X3, X4) >= b1

Which of the following statements is NOT true? a. a feasible solution satisfies all constraints b. an optimal solution satisfies all constraints c. an infeasible solution violates all constraints d. a feasible solution point does not have to lie on the boundary of the feasible region

c. an infeasible solution violates all constraints

A manager wants to ensure that he does not exceed his budget by more than $1,000 in a goal programming problem. If the budget constraint is the third constraint in the goal programming problem, which of the following formulas will best ensure that the manager's objective is met? a. MINd3+ b. d3− ≥ 1,000 c. d3+ = 1,000 d. d3+ ≤ 1,000

d. d3+ ≤ 1,000

if a time series plot exhibits a horizontal pattern, then __________. a. it is evident that the time series is stationary b. the data fluctuates around the variable mean c. there is no relationship between time and the time series variable d. there is still not enough evidence to conclude that the time series is stationary

d. there is still not enough evidence to conclude that the time series is stationary

a dummy origin in a transportation problem is used when supply exceeds demand T/F

False

a transshipment problem will have nine decision variables when there are three sources each connected to four destinations, through two transshipment notes T/F

False

an infeasible LP model can be fixed by changing the objective function T/F

False

the constraint Z1 - X2 = 0 implies that if project 1 is selected, project 2 cannot be T/F

False

In a linear programming problem, the objective function and the constraints must be linear functions of the decision variables T/F

True

in order to tell the impact of change in a constraint coefficient, the change must be made and then the model resolved T/F

True

Suppose that X1 equals 4. What are the values for d1+and d1− in the following constraint? X1+d1− − d1+=8 a. d1−=4 and d1+=0 b. d1−=0 and d1+=4 c. d1−=4 and d1+=4 d. d1−=8 and d1+=0

a. d1−=4 and d1+=0

in a linear regression model, the variable that is being predicted or explained is known as _____________. It is denoted by y and is often referred to as the response variable. a. dependent variable b. independent variable c. residual variable d. regression variable

a. dependent variable

The absolute value of the shadow price indicates the amount by which the objective function will be a. improved if the corresponding constraint is loosened b. improved if the corresponding constraint is tightened c. made worse if the corresponding constraint is unchanged d. improved if the corresponding constraint is unchanged

a. improved if the corresponding constraint is loosened

Assume an objective function has a value of 150 and the shadow price for resource 1 is 5 and the allowable increase for this resource is greater than 10. If 10 more units of resource 1 are added, what is the impact on the objective function value? a. increase of 50 b. increase of unknown amount c. decrease of 50 d. increase of 10

a. increase of 50

Which of the following are true regarding weights assigned to deviational variables? a. Larger weights are assigned to undesirable deviations from the respective goals. b. The weights assigned must sum to one. c. The weight assigned to the deviation under a particular goal must be the same as the weight assigned to the deviation above that particular goal. d. All weights must be nonzero.

a. larger weights are assigned to undesirable deviations form the respective goals

in what part(s) of a linear programming formulation would the decision variables be included? a. objective function and the left-hand side of each constraint b. objective function and the right-hand side of each constraint c. the left-hand side of each constraint only d. the objective function only

a. objective function and the left-hand side of each constraint

The Sanders Garden Shop mixes two types of grass seed into a blend. Each type of grass has been rated (per pound) according to its shade tolerance, ability to stand up to traffic, and drought resistance, as shown in the table. Type A seed costs $1 and Type B seed costs $2. The blend needs to score at least 300 points for shade tolerance, 400 points for traffic resistance, and 750 points for drought resistance. Which of the following LP models properly formulate the problem if management wants to know how many pounds of each seed should be in the blend and at what cost? Shade Tolerance A: 1 B: 1 Traffic Resistance A: 2 B: 1 Drought Resistance A: 2 B: 5 Let A = the pounds of Type A seed in the blend Let B = the pounds of Type B see in the blend a. min 1A + 2B ST 1A + 1B <= 300 2A + 1B <= 400 2A + 5B <= 750 A,B >= 0 b. min 1A + 2B ST 1A + 1B >= 300 2A + 1B >= 400 2A + 5B >= 750 A, B >= 0

b

a normally distributed error term with a mean of zero would _______________. a. have more values that are symmetric about the variance b. allow more accurate modeling c. yield biased regression estimates d. be a hyperbolic curve

b. allow more accurate modeling

a causal model provides evidence of _________ between an independent variable and the variable to be forecast a. a causal relationship b. an association c. no relationship d. a seasonal relationship

b. an association

the ____________ is a measure of the goodness of fit of the estimated regression equation. It can be interpreted as the proportion of variability in the dependent variable y that is explained by the estimated regression equation. a. residual b. coefficient of determination c. dummy variable d. interaction variable

b. coefficient of determination

limited resources are modeled in optimization problem as ______________ a. an objective function b. constraints c. decision variables d. alternatives

b. constraints

the decision variables of a model are also known as the _________ a. uncontrollable output b. controllable inputs c. environmental factors d. projected results

b. controllable inputs

a constraint which cannot be violated is called a _________________. a. binding constraint b. hard constraint c. definite constraint d. required constraint

b. hard constratint

__________ is the most critical step of the decision making process a. choosing an alternative b. identifying and defining the problem c. evaluating the alternatives d. determining the set of alternatives

b. identifying and defining the problem

Slack __________ a. is the difference between the left and right sides of the a constraint b. is the amount by which the left side of a < constraint is smaller than the right side c. is the amount by which the left side of a > constraint is larger than the right side d. exists for each variable in a linear programming problem

b. is the amount by which the left side of a < constraint is smaller than the right side

the allowable increase for a constraint is a. how many more units of a resource to purchase to maximize profits b. the amount by which the resource can increase the given shadow price c. how much resource to use to get the optimal solution d. the amount by which the constraint coefficient can increase without changing the final optimal value

b. the amount by which the resource can increase given shadow price

a binding greater than or equal to constraint in a minimization problem means that a. the variable is up against an upper limit b. the minimum requirement for the constraint has just been met c. another constraint is limiting the solution d. the shadow price for the constraint will be positive

b. the minimum requirement for the constraint has just been met

The shadow price of a non-binding constraint is a. positive b. zero c. negative d. intermediate

b. zero

when the mean value of the dependent variable is independent of variation in the independent variable, the slope of the regression line is ________________. a. positive b. zero c. negative d. infinite

b. zero

decision criteria ________________ a. are the choices faced by the decision maker b. are the problems faced by the decision maker c. are the ways to evaluate the choices faced by the decision maker d. must be unique for a problem

c. are the ways to evaluate the choices faced by the decision maker

In a business, the values indicating the current operating characteristics, such as financial position, inventory on hand, and customer service metrics, are typically known as ________________. a. company performance indicators b. performance indicators c. key performance indicators d. business performance indicators

c. key performance indicators

if the shadow price for a resource is 0 and 150 units of the resource are added what happens to the optimal solution a. increases by an unknown amount b. increases more than 0 but less than 150 c. no change d. decreases by an unknown amount

c. no change

which of the following analytical techniques helps us arrive at the best decision? a. predictive analytics b. data mining c. prescriptive analytics d. descriptive analytics

c. prescriptive analytics

The amount by which an objective function coefficient can change before a different set of values for the decision variables becomes optimal is the _______________. a. optimal solution b. alternative solution c. range of optimality d. range of feasibility

c. range of optimality

data-driven decision making tends to decrease a firm's _______ a. market value b. productivity c. risk d. profit

c. risk

with reference to time series date patterns, a cyclical pattern is the component of the time series that ___________________. a. shows a periodic pattern lasting one year or less b. does not vary with respect to time c. shows a periodic pattern lasting more than one year d. is characterized by a linear variation of the dependent variable with respect to time

c. shows a periodic pattern lasting more than one year

Tables should be used instead of charts when a. the reader needs relative comparisons of data b. there are more than two columns of data c. the values being displayed have different units or very different magnitudes d. the reader need not differentiate the columns and rows

c. the values being displayed have different units or very different magnitudes

goal programming differs from linear programming or integer linear programming in that _______________. a. goal programming provides for multiple objectives b. goal programming excludes hard constraints c. with goal programming we iterate until an acceptable solution is obtained d. goal programming requires fewer variables

c. with goal programming we iterate until an acceptable solution is obtained

Let X1 and X2 be 0-1 variables whose values indicate whether projects 1 and 2 are not done or are done. Which answer below indicates that project 2 can be done only if project 1 is done? a. X1 + X2 = 1 b. X1 + X2 = 2 c. X1 - X2 <= 0 d. X1 - X2 >= 0

d. X1 - X2 >= 0

Which of the following is true regarding goal programming? a. The objective function is not useful when comparing goal programming solutions. b. We can place upper bounds on any of the deviation variables c. A preemptive goal program involves deviations with arbitrarily large weights d. all of these are true

d. all of these are true

DJ needs to display data over time. Which of the following charts should he use? a. scatter chart b. pie chart c. bar chart d. line chart

d. line chart

the objective of the transportation problem is to _________. a. identify one origin that can satisfy total demand at the destinations and at the same time minimize total shipping cost b. minimize the number of origins used to satisfy total demand at the destinations c. minimize the number of shipments necessary to satisfy total demand at the destinations d. minimize the cost of shipping products from several origins to several destinations

d. minimize the cost of shipping products from several origins to several destinations

which of the following states the objective of time series analysis? a. to predict the values of a time series based on one or more other variables b. to analyze the cause-and-effect relationship of a dependent variable with a time series and one or more other variables c. to use present variable values to study what should have been the ideal past values d. to uncover a pattern in a time series and then extrapolate the pattern into the future

d. to uncover a pattern in a time series and then extrapolate the pattern into the future