Ch. 4 LS - Econ 221

When rolling a pair of dice and summing the two values rolled, which of the following are exhaustive events?

- An even number an an odd number - A value of 7 or more and a value of 6 or less - A value of 6 or more and a value of 8 or less

Which of the following events are mutually exclusive

- Being on time and being late for an appointment - Receiving an 'A' and receiving a 'B+' as a final grade in an Accounting class

The High Roller Casino puts the odds of a certain baseball team winning the World Series at 1 to 30 (1:30). Based on those odds, what is the probability that this baseball team will win the World Series?

0.032 1/1+30 = 0.032

The probability of randomly selecting a "spade" from a deck of cards is

0.25

Let P(A) = 0.3 and P(B) = 0.4. Suppose A and B are independent events. Calculate P(B|A).

0.40

The probability of Margaret receiving a promotion at XYZ corp. is 0.70. The probability of Kate receiving a promotion at ABC Inc. is 0.60. If the two promotions are independent, then the probability of both Margaret and Kate receiving a promotion is _____.

0.42 0.7 x 0.6 = 0.42

The probability of a customer purchasing popcorn at the movie theater is 0.3. What is the probability that a customer does not purchase popcorn.

0.7

Corky and Lori process purchase orders for Acme Inc. Lori processes 60% of the purchase orders; Corky processes 40% of the purchase orders. While 5% of Lori's purchase orders have errors, only 2.5% of Corky's purchase orders have errors. A purchase order has an error; the probability that Lori processed the erroneous purchase order is _____.

0.75 E=error; L=Lori; C=Corky, or the compliment of Lori P(L|E) = P(E|L) x P(L)/ P(E|L) x P(L) + P(E|C) xP(C) = .05x.6/ .05x.6 + .025x.4 = .03/.04 = 0.75

The odds against a horse winning a race were set at 7 to 1. The probability of that horse not winning the race is

0.875 7/1+7 = 0.875

Kareem is trying to decide which college to attend full time next year. Kareem believes there is a 55% chance that he will attend State College and a 33% chance that he will attend Northern University. The probability that Kareem will attend either State or Northern is _____.

0.88

A festival has become so popular that is must limit the number of tickets it issues. People who hope to attend the festival send in a request for tickets, and requests are filled by random selection. Only 21% of the ticket requests are fulfilled. The odds that a random applicant does NOT receive a ticket are.

3.76 to 1 1-0.21/ 0.21

The compliment of event A within the sample space S contains

All outcomes in S that are not in A

When updating a prior probability based on new information, which of the following methodologies is MOST useful?

Bayes' Theorem

A probability based on logical analysis rather than on observation on personal judgement is BEST referred to as a(n):

Classical probability

A _____ probability is the probability of an event given that another event has already occurred.

Conditional

The total probability rule is used to compute an unconditional probability of an event by using

Conditional probabilities

For hotels in New York City, a travel web site wants to provide information comparing hotel costs (high, average, low) versus the quality ranking of the hotel (excellent, good, fair, poor). A useful way to summarize this data is to construct a(n) _____.

Contingency table

The probability of Murali going to the coffee shop is 0.70. The probability of Connie going to the coffee shop is 0.40. If Murali goes to the coffee shop, the probability of Connie going to the coffee shop is 0.48. The events Murali going to the coffee shop and Connie going to the coffee shop are

Dependent

A subset of the sample space is a/an

Event

Events that include all outcomes in the sample space are known as _____ events.

Exhaustive

A trial, or process, that produces several possible outcomes is referred to as a(n) _____.

Experiment

The sum of the probabilities of a list of mutually exclusive and exhaustive events is

One

For two events A and B, the multiplication rule is

P(A | B)P(B) - B occurs first. Then A happens second given that B has already occurred

The addition rule for two events A and B is

P(A) + P(B) - P(A (upsidedown u) B)

If A and B are independent events, then

P(A) = P(A|B)

Assume the sample space of S = {win, loss}. Select the choice that fulfills the requirements of the definition of probability

P({win}) = 0.8, P({loss}) = 0.2

A probability based on personal judgement rather than on observation or logical analysis is best referred to as a(n)_____.

Subjective probability

If an experiment is selecting a card from a deck of cards, then the sample space is

all the cards in the deck

The relative frequency of an event is used to calculate what type of probability?

an empirical probability

If two events are independent, then the probability that both events occur equals

the product of the individual probabilities

In order to convert a contingency table into a joint probability table, the frequency of each cell is divided by the _____.

total number of outcomes in the sample space

Probability values range from

zero to one