Quantitative Methods Exam Ch 1-3

If P(A) = 0.38, P(B) = 0.83, and P(A B) = 0.27; then P(A B) =

0.94

For a standard normal distribution, the probability of obtaining a z value of less than 1.6 is

0.9452

A standard normal distribution is a normal distribution with

a mean of 0 and a standard deviation of 1

A numerical description of the outcome of an experiment is

a random variable.

An element of the sample space is

a sample point

A graphical device used for enumerating sample points in a multiple-step experiment is a

a. pie chart *****b.None of the other answers is correct.******* c.bar chart d.histogram

An experiment consists of tossing 4 coins successively. The number of sample points in this experiment is

16

Events A and B are mutually exclusive. Which of the following statements is also true?

A and B are also independent

The expected value for a binomial probability distribution is

E(x) = np

A feasible solution is one that satisfies at least one of the constraints in the problem.

False

A graphical device used for enumerating sample points in a multiple-step experiment is a Venn diagram.

False

For an exponentially distributed random variable x with a mean of 8, the probability of x ≤ 8 is .5.

False

Model development should be left to quantitative analysts; the model user's involvement should begin at the implementation stage.

False

P(A B) ≥ P(A)

False

P(A|B) = 1 − P(B|A) for all events A and B.

False

The intersection of A and Ac is the entire sample space.

False

If P(A|B) = .4, then

P(A)*P(B) = .4 b.P(B|A) = .6 c.P(A) / P(B) = .4 *******d.None of the alternatives is correct.*******

If x is normally distributed with mean 12 and standard deviation 2, then P(x ≤ 9) is

P(z ≤ −3/2)

If one wanted to find the probability of ten customer arrivals in an hour at a service station, one would generally use the

Poisson probability distribution

When the conclusions based upon the aggregated crosstabulation can be completely reversed if we look at the unaggregated data, the occurrence is known as

Simpson's paradox

A posterior probability is a conditional probability.

True

A random variable that can take on any value along a line segment is a continuous random variable.

True

A random variable that may assume only a finite or an infinite sequence (e.g., 1, 2, 3,...) of values is a discrete random variable.

True

All uncontrollable inputs or data must be specified before we can analyze the model and recommend a decision or solution for the problem.

True

If 50 of 250 people contacted make a donation to the city symphony, then the relative frequency method assigns a probability of .2 to the outcome of making a donation.

True

If A and B are independent events, then P(A B) = P(A)P(B).

True

If P(A B) = P(A) + P(B), then A and B are mutually exclusive.

True

If you are deciding to buy either machine A, B, or C with the objective of minimizing the sum of labor, material and utility costs, you are dealing with a single-criterion decision.

True

The most critical component in determining the success or failure of any quantitative approach to decision making is problem definition.

True

Two events that are mutually exclusive cannot be independent.

True

When assigning subjective probabilities, use experience, intuition, and any available data.

True

The weight of an object, measured to the nearest gram, is an example of

a discrete random variable

The field of management science

a.is another name for decision science and for operations research. *******b.each of these choices are true.******* c.approaches decision making rationally, with techniques based on the scientific method. d.concentrates on the use of quantitative methods to assist in decision making.

A method of assigning probabilities based upon judgment is referred to as the

a.relative method b.classical method c.probability method *****d.None of the alternatives is correct.*******

In the set of all past due accounts, let the event A mean the account is between 31 and 60 days past due and the event B mean the account is that of a new customer. The complement of A is

all accounts fewer than 31 or more than 60 days past due.

The union of events A and B is the event containing

all the sample points belonging to A or B or both

Decision criteria

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

The volume that results in total revenue being equal to total cost is the

break-even point.

Experimental outcomes that are based on measurement scales such as time, weight, and distance can be described by _____ random variables.

continuous

A probability density function

describes the graph whose underlying area represents probability over an interval.

Before drawing any conclusions about the relationship between two variables shown in a crosstabulation, you should

investigate whether any hidden variables could affect the conclusions

Identification and definition of a problem

is the first step of decision making.

The probability of an event

is the sum of the probabilities of the sample points in the event.

The quantitative analysis approach requires

mathematical expressions for the relationships

A model that uses a system of symbols to represent a problem is called

mathematical.

A binomial probability distribution with p = .3 is

negatively skewed

Management science and operations research both involve

quantitative approaches to decision making.

Which of the following is not a property of a binomial experiment?

the probabilities of the two outcomes can change from one trial to the next

A physical model that has the same physical appearance as the object being modeled is

​an iconic model

Which of the following is not one of the commonly used names for the body of knowledge involving quantitative approaches to decision-making?

​efficiency studies