Question 1

What may NOT be said about the mean of a discrete random variable x?

Accepted Answer

A)  It is denoted by. 
B)  It is the middle value of its probability distribution. 
C)  It is denoted by E(x), because it is the value of x one can expect to find, on average, by numerous repetitions of the random experiment that generates the variable's actual values. 
D)  It is correctly described by both (a) and (b). 
A)  It is denoted by. 
B)  It is the middle value of its probability distribution. 
C)  It is denoted by E(x), because it is the value of x one can expect to find, on average, by numerous repetitions of the random experiment that generates the variable's actual values. 
D)  It is correctly described by both (a) and (b). B

Question 2

Suppose P(A) = 0.4, P(B) = 0.3, and P(A   B) = 0. Which one of the following statements correctly defines the relationship between events A and B?

Accepted Answer

A)  Events A and B are independent, but not mutually exclusive. 
B)  Events A and B are mutually exclusive, but not independent. 
C)  Events A and B are neither mutually exclusive nor independent. 
D)  Events A and B are both mutually exclusive and independent. 
A)  Events A and B are independent, but not mutually exclusive. 
B)  Events A and B are mutually exclusive, but not independent. 
C)  Events A and B are neither mutually exclusive nor independent. 
D)  Events A and B are both mutually exclusive and independent. B

Question 3

What is the sum of the probability of an event and the probability of its complement?

Accepted Answer

A)  -1 
B)  0 
C)  1 
D)  any value between 0 and 1 
A)  -1 
B)  0 
C)  1 
D)  any value between 0 and 1 C

Question 4

Different events that have no outcomes in common are mutually exclusive events.

Accepted Answer

A) True 
 B)False

Question 5

Two events, A and B, are said to be dependent if and only if what condition is true?

Accepted Answer

A)  P(
A)  = P(
B) . 
B)  P(
A)  increases along with P(
B) . 
C)  P(
A)  increases as P(
B)  decreases. 
D)  Event A is affected or changed by the occurrence of event B. 
A)  P(
A)  = P(
B) . 
B)  P(
A)  increases along with P(
B) . 
C)  P(
A)  increases as P(
B)  decreases. 
D)  Event A is affected or changed by the occurrence of event B.

Question 6

The conditional probability of event B, given that event A has occurred is defined by   .

Accepted Answer

A) True 
 B)False

Question 7

If P(A) = 0.80, P(B) = 0.70, and P(A   B) = 0.90, then what is the value of P(A   B)?

Accepted Answer

A)  0.56 
B)  0.60 
C)  0.63 
D)  0.72 
A)  0.56 
B)  0.60 
C)  0.63 
D)  0.72

Question 8

If P(A) > 0 and P(B) > 0, then when A and B are mutually exclusive events, they are also dependent events.

Accepted Answer

A) True 
 B)False

Question 9

The probability of getting a 15 when randomly drawing a card from a well-shuffled deck is 4/52.

Accepted Answer

A) True 
 B)False

Question 10

Two events A and B are said to be independent if and only if P(A/B) = P(B) or P(B/A) = P(A).

Accepted Answer

A) True 
 B)False

Question 11

In the case of independent events A, B, and C, which of the following is equal to   ?

Accepted Answer

A)  P(A|
B) P(B|
C) P(C|
A)  
B)  P(A|
B)  + P(B|
C)  + P(C|
A)  
C)  P(
A) P(
B) P(
C)  
D)  P(
A)  + P(
B)  + P(
C)  
A)  P(A|
B) P(B|
C) P(C|
A)  
B)  P(A|
B)  + P(B|
C)  + P(C|
A)  
C)  P(
A) P(
B) P(
C)  
D)  P(
A)  + P(
B)  + P(
C)

Question 12

The intersection of events A and B is the event that A or B or both occur.

Accepted Answer

A) True 
 B)False

Question 13

If P(A) = 0.30, P(B) = 0.40, and P(A   B) = 0.20, what is the value of P(A/B)?

Accepted Answer

A)  0.08 
B)  0.12 
C)  0.50 
D)  0.67 
A)  0.08 
B)  0.12 
C)  0.50 
D)  0.67

Question 14

The probability that event A will not occur is 1 -   .

Accepted Answer

A) True 
 B)False

Question 15

Which of the following best describes the concept of marginal probability?

Accepted Answer

A)  It is a measure of the likelihood that a particular event will occur, regardless of whether another event occurs. 
B)  It is a measure of the likelihood that a particular event will occur, given the fact that another event has already occurred or is certain to occur. 
C)  It is a measure of the likelihood of the simultaneous occurrence of two or more events. 
D)  It is a direct way for defining the sample space of an experiment.
It is measure of the likelihood that either one or the other out of a possible two events will occur. 
A)  It is a measure of the likelihood that a particular event will occur, regardless of whether another event occurs. 
B)  It is a measure of the likelihood that a particular event will occur, given the fact that another event has already occurred or is certain to occur. 
C)  It is a measure of the likelihood of the simultaneous occurrence of two or more events. 
D)  It is a direct way for defining the sample space of an experiment.
It is measure of the likelihood that either one or the other out of a possible two events will occur.

Question 16

An experiment is the process by which an observation or measurement is obtained.

Accepted Answer

A) True 
 B)False

Question 17

If A and B are dependent events, they are also mutually exclusive.

Accepted Answer

A) True 
 B)False

Question 18

The number of homes sold by a real estate agency in a three-week period is an example of a continuous random variable.

Accepted Answer

A) True 
 B)False

Question 19

A random variable is any variable for which the numerical value is determined by a random experiment, and, thus, by chance.

Accepted Answer

A) True 
 B)False

Question 20

When Cynthia enters a grocery store, there are three simple events: buy nothing, buy a small amount, or buy a large amount. In this situation, if Cynthia buys a small amount, she cannot also buy a large amount or buy nothing. How may one best classify these three events?

Accepted Answer

A)  They are mutually exclusive events. 
B)  They are not mutually exclusive events. 
C)  They are dependent events. 
D)  They are independent events. 
A)  They are mutually exclusive events. 
B)  They are not mutually exclusive events. 
C)  They are dependent events. 
D)  They are independent events.

Exam 4: A: probability and Probability Distributions

What may NOT be said about the mean of a discrete random variable x?

Suppose P(A) = 0.4, P(B) = 0.3, and P(A B) = 0. Which one of the following statements correctly defines the relationship between events A and B?

What is the sum of the probability of an event and the probability of its complement?

Different events that have no outcomes in common are mutually exclusive events.

Two events, A and B, are said to be dependent if and only if what condition is true?

The conditional probability of event B, given that event A has occurred is defined by .

If P(A) = 0.80, P(B) = 0.70, and P(A B) = 0.90, then what is the value of P(A B)?

If P(A) > 0 and P(B) > 0, then when A and B are mutually exclusive events, they are also dependent events.

The probability of getting a 15 when randomly drawing a card from a well-shuffled deck is 4/52.

Two events A and B are said to be independent if and only if P(A/B) = P(B) or P(B/A) = P(A).

In the case of independent events A, B, and C, which of the following is equal to ?

The intersection of events A and B is the event that A or B or both occur.

If P(A) = 0.30, P(B) = 0.40, and P(A B) = 0.20, what is the value of P(A/B)?

The probability that event A will not occur is 1 - .

Which of the following best describes the concept of marginal probability?

An experiment is the process by which an observation or measurement is obtained.

If A and B are dependent events, they are also mutually exclusive.

The number of homes sold by a real estate agency in a three-week period is an example of a continuous random variable.

A random variable is any variable for which the numerical value is determined by a random experiment, and, thus, by chance.

When Cynthia enters a grocery store, there are three simple events: buy nothing, buy a small amount, or buy a large amount. In this situation, if Cynthia buys a small amount, she cannot also buy a large amount or buy nothing. How may one best classify these three events?

Describing Data With Graphs

Describing Data With Numerical Measures

Describing Bivariate Data

B: probability and Probability Distributions

Several Useful Discrete Distributions

The Normal Probability Distribution

Sampling Distributions

Large-Sample Estimation

A: large-Sample Tests of Hypotheses

B: large-Sample Tests of Hypotheses

A: Inference From Small Samples

B: Inference From Small Samples

A: The Analysis of Variance

B: The Analysis of Variance

A: linear Regression and Correlation

B: linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

A:nonparametric Statistics

B:nonparametric Statistics

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