business stats ch 4

The values in the margins of a contingency table represent _____ probabilities.

unconditional or marginal

The ___ of two events is the event consisting of all outcomes in A or B.

union

To calculate the probability of the union of two mutually exclusive events A and B

we add the probability of A to the probability of B.

Probability values range from...

zero to one.

A(n) ______ of an experiment contains all possible outcomes of the experiment.

sample space

The complement rule with respect to event A is...

P(A^c) = 1 - P(A)

If A and B are independent events, which of the following is correct?

P(A|B)=P(A)

The addition rule for two events A and B is...

P(A∪B) = P(A) + P(B) - P(A∩B)

Let A and B be two independent events with P(A) = 0.40 and P(B) = 0.20. Which of the following is correct?

P(A∪B)=0.52

The contingency table below provides frequencies for the preferred type of exercise for people under the age of 35, and those 35 years of age or older. Find the probability that an individual prefers biking given that he or she is 35 years old or older.

.1698

Two hundred people were asked if they had read a book in the last month. The accompanying contingency table, cross-classified by age, is produced. Under 3030+Yes7665No2435 The probability that a respondent read a book in the last month and is at least 30 years old is the closest to _______

.33

The 150 residents of the town of Wonderland were asked their age and whether they preferred vanilla, chocolate, or swirled frozen yogurt. The results are displayed next. ChocolateVanillaSwirlUnder 25 years old402015At least 25 years old154020 What is the probability that a randomly selected customer prefers vanilla?

.40

Two hundred people were asked if they had read a book in the last month. The accompanying contingency table, cross-classified by age, is produced. Under 3030+Yes7665No2435 The probability that a respondent is at least 30 years old is the closest to ______.

.50

For mutually exclusive events A and B, the joint probability is

0

The likelihood of Company A's stock price rising is 20%, and the likelihood of Company B's stock price rising is 30%. Assume that the returns of Company A and Company B stock are independent of each other. The probability that the stock price of at least one of the companies will rise is ______.

44%

from here quiz begins What is probability?

A value between 0 and 1 assigned to an event that measures the likelihood of its occurrence.

What is a simple event?

An event that contains only one outcome of a sample space

The conditional probability of A given B is calculated by dividing the probability of intersection of A and B by the probability of __

B

_____ probabilities are often used in games of chance.

Classical

Which of the following sets of outcomes described below in I and II represent mutually exclusive events? "Your final course grade is an A"; "Your final course grade is a B." "Your final course grade is an A"; "Your final course grade is a Pass."

Only I represents mutually exclusive events.

The ____ rule allows us to find the probability of the union of two events.

addition

With probability, a value of one indicates a ______ event

certain

A probability based on logical analysis rather than on observation or personal judgment 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

Mutually exclusive and exhaustive events Multiple choice question. contain all outcomes in an experiment and may share common outcomes. contain all outcomes in an experiment and do not share common outcomes. may not contain all outcomes in an experiment.

contain all outcomes in an experiment and do not share common outcomes.

In a contingency table, joint probabilities represent the ____ of two events

intersection

P(A ∩ B) is known as a ______ probabilty

joint

subjective probability

the individual's personal estimate of the chance of loss

Peter applied to an accounting firm and a consulting firm. He knows that 30% of similarly qualified applicants receive job offers from the accounting firm, while only 20% of similarly qualified applicants receive job offers from the consulting firm. Assume that receiving an offer from one firm is independent of receiving an offer from the other. What is the probability that both firms offer Peter a job?

0.06

The union of two events A and B, denoted A∪B, contains

all outcomes in A or B.

A sample space contains _________________.

all possible outcomes of an experiment

The contingency table below provides frequencies for the preferred type of exercise for people under the age of 35 and those 35 years of age or older. Find the probability that an individual prefers running. Age GroupPreferred Form of ExerciseTotalRunningBikingSwimmingUnder 35 years1571217935735 years or older452787159Total202148166516

0.3915

Let P(A)=0.3 and P(B)=0.4.P(A)=0.3⁢ and⁢ ⁢P(B)=0.4. Suppose A and B are independent. What is the value of P(B|A)?

0.4

Which of the following represents a subjective probability?

A skier believes she has a 10% chance of winning a gold medal.

A subset of the sample space is called a/an

event

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

An empirical probability

Mutually exclusive events _____________.

do not share common outcomes

Mutually exclusive events

do not share common outcomes of the experiment.

The values in the interior of a contingency table represent _____ probabilities

joint

P(A ∩ B) = P(A|B)P(B) is referred to as the ________ rule for probabilities

multiplication

How many outcomes of an experiment constitute a simple event?

one

The addition rule is used to calculate...

the union of two events

how to tell if events are exhaustive or not

they are exhaustive if the 2 events contain all the numbers in the sample space

Events are collectively exhaustive if _____________.

they contain all outcomes of an experiment

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

Marginal probabilities are also known as _____ probabilities.

unconditional

Assume the sample space S = {win, loss}. Which numbers define valid probabilities? Multiple choice question. P({win}) = 0.8, P({loss}) = 0.3 P({win}) = 1.0, P({loss}) = -1.0 P({win}) = 0.8, P({loss}) = 0.2 P({win}) = 0.8, P({loss}) = 0.1

P({win}) = 0.8, P({loss}) = 0.2 The sum of the probabilities of exhaustive and mutually exclusive events must be 1.0.