Question 1

A therapist goes through her records and finds that 200 of her 400 patients showed significant improvement in mental health over the past year.Hence,the probability of her patients showing significant improvement in mental health is ______.

Accepted Answer

A)  .05 
B)  .50 
C)  200 
D)  400

Question 2

The probability of a student attending every college class is p = .26.The probability of a student attending every college class and earning an A is p = .22.Hence,the probability of a student earning an A,given that he or she attends every college class,is ______.

Accepted Answer

A)  p = .06 
B)  p = .48 
C)  p = .85 
D)  There is not enough information to answer this question.

Question 3

Probability distributions display the probability of each possible outcome for a given random variable.

Accepted Answer

A) True 
 B)False

Question 4

The sample space is equal to the total number of random outcomes possible for a random variable.

Accepted Answer

A) True 
 B)False

Question 5

A researcher records the number of job openings among small businesses.She finds that the probability that a small business has 0 job openings is p = .22; 1 job opening is p = .45; 2 job openings is p = .08; and 3 job openings is p = .25.What is the probability that a small business has at least 2 job openings?

Accepted Answer

A)  .08 
B)  .25 
C)  .33 
D)  .67

Question 6

Bayes's theorem is often applied to a variety of conditional probability situations,including those related to statistical inference.

Accepted Answer

A) True 
 B)False

Question 7

The following probability distribution for outcomes 0,1,2,and 3,respectively,is possible: 18/30,3/30,4/30,and 5/30.

Accepted Answer

A) True 
 B)False

Question 8

A news poll showed that voters had no preference for either of three candidates.In this example,the probability of a vote for,say,Candidate A equals ______.

Accepted Answer

A)  1/2 
B)  1/3 
C)  2/3 
D)  1.00

Question 9

The mean of a probability distribution is called the

Accepted Answer

A)  expected value of the mean. 
B)  mathematical expectation. 
C)  expected value of the mean and mathematical expectation. 
D)  none of these.

Question 10

Below is the probability distribution for random variable x.What is the standard deviation of this probability distribution?

Accepted Answer

A)  6.20 
B)  2.49 
C)  1.00 
D)  0.35

Question 11

Bayes's theorem is often applied to a variety of ______ probability situations,including those related to statistical inference.

Accepted Answer

A)  generic 
B)  absolute 
C)  conditional 
D)  fixed

Question 12

The probability of a college student being employed is p = .35.The probability of a student being employed and dropping out of college is p = .20.Hence,the probability of a student dropping out of college,given that he or she is employed,is ______.

Accepted Answer

A)  p = .07 
B)  p = .57 
C)  p = .55 
D)  There is not enough information to answer this question.

Question 13

If the variance of a probability distribution is 121,then the standard deviation is ______.

Accepted Answer

A)  121 
B)  21 
C)  12 
D)  11

Question 14

A researcher determines that the probability of winning a new game is p = .32.Assuming winning and losing are mutually exclusive events,what is the probability of winning and losing the new game?

Accepted Answer

A)  .32 
B)  .64 
C)  1.00 
D)  This outcome is not possible, p = 0.

Question 15

A professor records the grades for his class students.He finds that the probability that a student earns an A is p = .14; earns a B is p = .36; earns a C is p = .32; earns a D is p = .10; and earns an F is p = .08.What is the probability that a student earns a B or better in this class?

Accepted Answer

A)  .36 
B)  .14 
C)  .86 
D)  .50

Question 16

A researcher visits a population of 1,200 local residents to determine the proportion of local residents who support a new smoking ban.In this case,the sample space is

Accepted Answer

A)  equal to the number of residents who support the new smoking ban. 
B)  equal to the population of 1,200 local residents. 
C)  equal to the number of local residents who smoke. 
D)  unknown.

Question 17

Below is the probability distribution for random variable x.Which of the following is most probable?

Accepted Answer

A)  a score of at most 13 
B)  a score of at least 13 
C)  a score of 12 
D)  a score of 14

Question 18

Bayes's theorem is a conditional probability formula.

Accepted Answer

A) True 
 B)False

Question 19

Below is the probability distribution for the number of times students had to take the same exam before passing it.If a student must pass the exam in two tries or less to pass the class,then what is the probability of passing the class?

Accepted Answer

A)  .80 
B)  .40 
C)  .20 
D)  .10

Question 20

The probability of an outcome can be any positive value.

Accepted Answer

A) True 
 B)False

Exam 5: Probability

A therapist goes through her records and finds that 200 of her 400 patients showed significant improvement in mental health over the past year.Hence,the probability of her patients showing significant improvement in mental health is ______.

The probability of a student attending every college class is p = .26.The probability of a student attending every college class and earning an A is p = .22.Hence,the probability of a student earning an A,given that he or she attends every college class,is ______.

Probability distributions display the probability of each possible outcome for a given random variable.

The sample space is equal to the total number of random outcomes possible for a random variable.

Bayes's theorem is often applied to a variety of conditional probability situations,including those related to statistical inference.

The following probability distribution for outcomes 0,1,2,and 3,respectively,is possible: 18/30,3/30,4/30,and 5/30.

A news poll showed that voters had no preference for either of three candidates.In this example,the probability of a vote for,say,Candidate A equals ______.

The mean of a probability distribution is called the

Below is the probability distribution for random variable x.What is the standard deviation of this probability distribution?

Bayes's theorem is often applied to a variety of ______ probability situations,including those related to statistical inference.

The probability of a college student being employed is p = .35.The probability of a student being employed and dropping out of college is p = .20.Hence,the probability of a student dropping out of college,given that he or she is employed,is ______.

If the variance of a probability distribution is 121,then the standard deviation is ______.

A researcher determines that the probability of winning a new game is p = .32.Assuming winning and losing are mutually exclusive events,what is the probability of winning and losing the new game?

A professor records the grades for his class students.He finds that the probability that a student earns an A is p = .14; earns a B is p = .36; earns a C is p = .32; earns a D is p = .10; and earns an F is p = .08.What is the probability that a student earns a B or better in this class?

A researcher visits a population of 1,200 local residents to determine the proportion of local residents who support a new smoking ban.In this case,the sample space is

Below is the probability distribution for random variable x.Which of the following is most probable?

Bayes's theorem is a conditional probability formula.

Below is the probability distribution for the number of times students had to take the same exam before passing it.If a student must pass the exam in two tries or less to pass the class,then what is the probability of passing the class?

The probability of an outcome can be any positive value.