Chapter 05
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WebQuizzing – Ch.05
Book ISBN-10 0538477490
Book ISBN-13 9780538477499
Author: Gerald Keller
Title: Statistics for Management and Economics
Ed: 9e
# Questions Submitted: 20 Multiple Choice
1. An approach of assigning probabilities which assumes that all outcomes of the experiment
are equally likely is referred to as the:
A. subjective approach.
B. objective approach.
C. classical approach.
D. relative frequency approach.
Analysis:
A. Incorrect. It is referred to as the classical approach.
B. Incorrect. It is referred to as the classical approach.
C. Correct. It is referred to as the classical approach.
D. Incorrect. It is referred to as the classical approach.
ANSWER: C Ref: Section 5.1
2. If A and B are mutually exclusive events with P(A) = 0.70, then P(B):
A. can be any value between 0 and 1.
B. can be any value between 0 and 0.70.
C. cannot be larger than 0.30.
D. equals 0.30.
Analysis:
A. Incorrect. If A and B are mutually exclusive events with P(A) = 0.70, then P(B) cannot be
larger than 0.30.
B. Incorrect. If A and B are mutually exclusive events with P(A) = 0.70, then P(B) cannot be
larger than 0.30.
C. Correct. If A and B are mutually exclusive events with P(A) = 0.70, then P(B) cannot be larger
than 0.30.
D. Incorrect. If A and B are mutually exclusive events with P(A) = 0.70, then P(B) cannot be
larger than 0.30.
ANSWER: C Ref: Section 5.1
3. The collection of all possible outcomes of an experiment is called:
A. a simple event.
B. a sample space.
C. a sample.
D. a population.
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Analysis:
A. Incorrect. The collection of all possible outcomes of an experiment is called a sample space.
B. Correct. The collection of all possible outcomes of an experiment is called a sample space.
C. Incorrect. The collection of all possible outcomes of an experiment is called a sample space.
D. Incorrect. The collection of all possible outcomes of an experiment is called a sample space.
ANSWER: B Ref: Section 5.1
4. Which of the following is an approach to assigning probabilities?
A. Classical approach.
B. Relative frequency approach.
C. Subjective approach.
D. All of these choices are true.
Analysis:
A. Incorrect. Relative frequency approach is an approach to assigning probabilities.
B. Correct. Relative frequency approach is an approach to assigning probabilities.
C. Incorrect. Relative frequency approach is an approach to assigning probabilities.
D. Incorrect. Relative frequency approach is an approach to assigning probabilities.
ANSWER: B Ref: Section 5.1
5. If you roll a balanced die 50 times, you should expect an even number to appear:
A. on every other roll.
B. exactly 50 times out of 100 rolls
C. 25 times on average, over the long term.
D. All of these choices are true.
Analysis:
A. Incorrect. All of these choices are true.
B. Incorrect. All of these choices are true.
C. Incorrect. All of these choices are true.
D. Correct. All of these choices are true.
ANSWER: D Ref: Section 5.1
6. Which of the following best describes the concept of marginal probability?
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, if another event has
already occurred.
C. It is a measure of the likelihood of the simultaneous occurrence of two or more events.
D. None of these choices.
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Analysis:
A. Correct. The concept of marginal probability is a measure of the likelihood that a particular
event will occur, regardless of whether another event occurs.
B. Incorrect.The concept of marginal probability is a measure of the likelihood that a particular
event will occur, regardless of whether another event occurs.
C. Incorrect.The concept of marginal probability is a measure of the likelihood that a particular
event will occur, regardless of whether another event occurs.
D. Incorrect.The concept of marginal probability is a measure of the likelihood that a particular
event will occur, regardless of whether another event occurs.
ANSWER: A Ref: Section 5.2
7. The probability of the intersection of two events A and B is denoted by P(A and B) and is
called the:
A. marginal probability.
B. joint probability.
C. conditional probability of A given B.
D. conditional probability of B given A.
Analysis:
A. Incorrect. It is called the joint probability.
B. Correct. It is called the joint probability.
C. Incorrect. It is called the joint probability.
D. Incorrect. It is called the joint probability.
ANSWER: B Ref: Section 5.2
8. If two events are independent, what is the probability that they both occur?
A. 0
B. 0.50
C. 1.00
D. It cannot be determined from the information given.
Analysis:
A. Incorrect. It cannot be determined from the information given.
B. Incorrect. It cannot be determined from the information given.
C. Incorrect. It cannot be determined from the information given.
D. Correct. It cannot be determined from the information given.
ANSWER: D Ref: Section 5.2
9. If the outcome of event A is not affected by event B, then events A and B are said to be
A. mutually exclusive.
B. independent.
C. collectively exhaustive.
D. None of these choices.
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Analysis:
A. Incorrect. Events A and B are said to be independent.
B. Correct. Events A and B are said to be independent.
C. Incorrect. Events A and B are said to be independent.
D. Incorrect. Events A and B are said to be independent.
ANSWER: B Ref: Section 5.2
10. If A and B are independent events with P(A) = 0.60 and P(A|B) = 0.60, then P(B) is:
A. 1.20
B. 0.60
C. 0.36
D. Cannot be determined with the information given.
Analysis:
A. Incorrect. Cannot be determined with the information given.
B. Incorrect. Cannot be determined with the information given.
C. Incorrect. Cannot be determined with the information given.
D. Correct. Cannot be determined with the information given.
ANSWER: D Ref: Section 5.2
11. If events A and B are independent then:
A. P(A and B) = P(A)* P(B)
B. P(A and B) = P(A) + P(B)
C. P(B|A) = P(A)
D. None of these choices.
Analysis:
A. Correct. P(A and B) = P(A)* P(B)
B. Incorrect. P(A and B) = P(A)* P(B)
C. Incorrect. P(A and B) = P(A)* P(B)
D. Incorrect. P(A and B) = P(A)* P(B)
ANSWER: A Ref: Section 5.2 - 5.3
12. Two events A and B are said to be mutually exclusive if:
A. P(A|B) = 1
B. P(A|B) = P(A)
C. P(A and B) =1
D. P(A and B) = 0
Analysis:
A. Incorrect. If P(A and B) = 0
B. Incorrect. If P(A and B) = 0
C. Incorrect. If P(A and B) = 0
D. Correct. If P(A and B) = 0
ANSWER: D Ref: Section 5.2 - 5.3
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13. Which of the following statements is always correct?
A. P(A and B) = P(A) * P(B)
B. P(A or B) = P(A) + P(B)
C. P(A)= 1-P(Ac)
D. None of these choices.
Analysis:
A. Incorrect. P(A)= 1-P(Ac) is always correct.
B. Incorrect. P(A)= 1-P(Ac) is always correct.
C. Correct. P(A)= 1-P(Ac) is always correct.
D. Incorrect. P(A)= 1-P(Ac) is always correct.
ANSWER: C Ref: Section 5.2 - 5.3
14. If A and B are any two events with P(A) = .8 and P(B|Ac) = .7, then P(Ac and B) is
A. 0.56
B. 0.14
C. 1.50
D. None of these choices.
Analysis:
A. Incorrect. P(Ac and B) is 0.14
B. Correct. P(Ac and B) is 0.14
C. Incorrect. P(Ac and B) is 0.14
D. Incorrect. P(Ac and B) is 0.14
ANSWER: B Ref: Section 5.2 - 5.3