chap04-TIF-BSAFC5
CHAPTER 4: BASIC PROBABILITY
1.If two events are collectively exhaustive, what is the probability that one or the other occurs?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
c
TYPE: MC DIFFICULTY: Easy
KEYWORDS: collectively exhaustive
2.If two events are collectively exhaustive, what is the probability that both occur at the same time?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
d
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: collectively exhaustive, mutually exclusive
EXPLANATION: We do not know if they are mutually exclusive.
3.If two events are mutually exclusive, what is the probability that one or the other occurs?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
d
TYPE: MC DIFFICULTY: moderate
KEYWORDS: collectively exhaustive, mutually exclusive
EXPLANATION: We do not know if they are collectively exhaustive.
4.If two events are mutually exclusive, what is the probability that both occur at the same time?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
a
TYPE: MC DIFFICULTY: Easy
KEYWORDS: mutually exclusive
5.If two events are mutually exclusive and collectively exhaustive, what is the probability that both
occur?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
a
TYPE: MC DIFFICULTY: Easy
KEYWORDS: collective exhaustive, mutually exclusive
6.If two events are mutually exclusive and collectively exhaustive, what is the probability that one
or the other occurs?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
c
TYPE: MC DIFFICULTY: Easy
KEYWORDS: collectively exhaustive, mutually exclusive
7.If events A and B are mutually exclusive and collectively exhaustive, what is the probability that
event A occurs?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
d
TYPE: MC DIFFICULTY: moderate
KEYWORDS: collectively exhaustive, mutually exclusive
EXPLANATION: We do not know if they are equally likely events.
8.If two equally likely events A and B are mutually exclusive and collectively exhaustive, what is
the probability that event A occurs?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
b
TYPE: MC DIFFICULTY: easy
KEYWORDS: collectively exhaustive, mutually exclusive
9.If two equally likely events A and B are mutually exclusive, what is the probability that event A
occurs?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
d
TYPE: MC DIFFICULTY: moderate
KEYWORDS: collectively exhaustive, mutually exclusive
EXPLANATION: We do not know if they are collectively exhaustive.
10.If two equally likely events A and B are collectively exhaustive, what is the probability that event
A occurs?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
d
TYPE: MC DIFFICULTY: moderate
KEYWORDS: collectively exhaustive, mutually exclusive
EXPLANATION: We do not know if they are mutually exclusive.
11.Selection of raffle tickets from a large bowl is an example of
a)sampling with replacement.
b)sampling without replacement.
c)subjective probability.
d)None of the above.
ANSWER:
b
TYPE: MC DIFFICULTY: Easy
KEYWORDS: sampling with replacement, sampling without replacement
12.If two events are independent, what is the probability that they both occur?
a)0.
b)0.50.
c) 1.00.
d)Cannot be determined from the information given.
ANSWER:
d
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: statistical independence
13. 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)statistically independent.
c)collectively exhaustive.
d)None of the above.
ANSWER:
b
TYPE: MC DIFFICULTY: Easy
KEYWORDS: statistical independence
14.If event A and event B cannot occur at the same time, then events A and B are said to be
a)mutually exclusive.
b)statistically independent.
c)collectively exhaustive.
d)None of the above.
ANSWER:
a
TYPE: MC DIFFICULTY: Easy
KEYWORDS: mutually exclusive
15.If either event A or event B must occur, then events A and B are said to be
a)mutually exclusive.
b)statistically independent.
c)collectively exhaustive.
d)None of the above.
ANSWER:
c
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: collectively exhaustive
16.The collection of all possible events is called
a) a simple probability.
b) a sample space.
c) a joint probability.
d)the null set.
ANSWER:
b
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: sample space
17.All the events in the sample space that are not part of the specified event are called
a)simple events.
b)joint events.
c)the sample space.
d)the complement of the event.
ANSWER:
d
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: sample space, complement
18.Simple probability is also called
a)marginal probability.
b)joint probability.
c)conditional probability.
d)Bayes' theorem.
ANSWER:
a
TYPE: MC DIFFICULTY: Easy
KEYWORDS: marginal probability
19.When using the general multiplication rule, P(A and B) is equal to
a)P(A|B)P(B).
b)P(A)P(B).
c)P(B)/P(A).
d)P(A)/P(B).
ANSWER:
a
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: multiplication rule
20.A business venture can result in the following outcomes (with their corresponding chance of
occurring in parentheses): Highly Successful (10%), Successful (25%), Break Even (25%), Disappointing (20%), and Highly Disappointing (?). If these are the only outcomes possible for the business venture, what is the chance that the business venture will be considered Highly Disappointing?
a)10%
b)15%
c)20%
d)25%
ANSWER:
c
TYPE: MC DIFFICULTY: Easy
KEYWORDS: marginal probability
21.A recent survey of banks revealed the following distribution for the interest rate being charged on
a home loan (based on a 30-year mortgage with a 10% down payment).
Interest Rate 7.0% 7.5%8.0%8.5%> 8.5%
Probability 0.12 0.23 0.24 0.35 0.06
If a bank is selected at random from this distribution, what is the chance that the interest rate charged on a home loan will exceed 8.0%?
a)0.06
b)0.41
c)0.59
d) 1.00
ANSWER:
b
TYPE: MC DIFFICULTY: Easy
KEYWORDS: marginal probability, addition rule
22.The employees of a company were surveyed on questions regarding their educational background
and marital status. Of the 600 employees, 400 had college degrees, 100 were single, and 60 were single college graduates. The probability that an employee of the company is single or has a college degree is:
a)0.10
b)0.25
c)0.667
d)0.733
ANSWER:
d
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: addition rule
23.The employees of a company were surveyed on questions regarding their educational background
and marital status. Of the 600 employees, 400 had college degrees, 100 were single, and 60 were single college graduates. The probability that an employee of the company is married and has a college degree is:
a)40/600
b)340/600
c)400/600
d)500/600
ANSWER:
b
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: joint probability
24.The employees of a company were surveyed on questions regarding their educational background
and marital status. Of the 600 employees, 400 had college degrees, 100 were single, and 60 were single college graduates. The probability that an employee of the company does not have a
college degree is:
a)0.10
b)0.33
c)0.67
d)0.75
ANSWER:
b
TYPE: MC DIFFICULTY: Easy
KEYWORDS: complement
25.The probability that house sales will increase in the next 6 months is estimated to be 0.25. The
probability that the interest rates on housing loans will go up in the same period is estimated to be
0.74. The probability that house sales or interest rates will go up during the next 6 months is
estimated to be 0.89. The probability that both house sales and interest rates will increase during the next 6 months is:
a)0.10
b)0.185
c)0.705
d)0.90
ANSWER:
a
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: joint probability
26.The probability that house sales will increase in the next 6 months is estimated to be 0.25. The
probability that the interest rates on housing loans will go up in the same period is estimated to be
0.74. The probability that house sales or interest rates will go up during the next 6 months is
estimated to be 0.89. The probability that neither house sales nor interest rates will increase
during the next 6 months is:
a)0.11
b)0.195
c)0.89
d)0.90
ANSWER:
a
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: joint probability, complement
27.The probability that house sales will increase in the next 6 months is estimated to be 0.25. The
probability that the interest rates on housing loans will go up in the same period is estimated to be
0.74. The probability that house sales or interest rates will go up during the next 6 months is
estimated to be 0.89. The probability that house sales will increase but interest rates will not during the next 6 months is:
a)0.065
b)0.15
c)0.51
d)0.89
ANSWER:
b
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: joint probability, complement
28.The probability that house sales will increase in the next 6 months is estimated to be 0.25. The
probability that the interest rates on housing loans will go up in the same period is estimated to be
0.74. The probability that house sales or interest rates will go up during the next 6 months is
estimated to be 0.89. The events of increase in house sales and increase in interest rates in the next 6 months are
a)statistically independent.
b)mutually exclusive.
c)collectively exhaustive.
d)None of the above.
ANSWER:
d
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: joint probability, statistical independence
EXPLANATION: They are not statistically independent.
29.The probability that house sales will increase in the next 6 months is estimated to be 0.25. The
probability that the interest rates on housing loans will go up in the same period is estimated to be
0.74. The probability that house sales or interest rates will go up during the next 6 months is
estimated to be 0.89. The events of increase in house sales and no increase in house sales in the next 6 months are
a)statistically independent.
b)mutually exclusive.
c)collectively exhaustive.
d)(b) and (c)
ANSWER:
d
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: mutually exclusive, collectively exhaustive, complement
30.The probability that a new advertising campaign will increase sales is assessed as being 0.80. The
probability that the cost of developing the new ad campaign can be kept within the original
budget allocation is 0.40. Assuming that the two events are independent, the probability that the cost is kept within budget and the campaign will increase sales is:
a)0.20
b)0.32
c)0.40
d)0.88
ANSWER:
b
TYPE: MC DIFFICULTY: Easy
KEYWORDS: statistical independence, joint probability, multiplication rule
31.The probability that a new advertising campaign will increase sales is assessed as being 0.80. The
probability that the cost of developing the new ad campaign can be kept within the original
budget allocation is 0.40. Assuming that the two events are independent, the probability that the cost is kept within budget or the campaign will increase sales is:
a)0.20
b)0.32
c)0.68
d)0.88
ANSWER:
d
TYPE: MC DIFFICULTY: Easy
KEYWORDS: statistical independence, multiplication rule, addition rule
32.The probability that a new advertising campaign will increase sales is assessed as being 0.80. The
probability that the cost of developing the new ad campaign can be kept within the original
budget allocation is 0.40. Assuming that the two events are independent, the probability that the cost is not kept within budget or the campaign will not increase sales is:
a)0.12
b)0.32
c)0.68
d)0.88
ANSWER:
c
TYPE: MC DIFFICULTY: Easy
KEYWORDS: statistical independence, multiplication rule, addition rule, complement
33.The probability that a new advertising campaign will increase sales is assessed as being 0.80. The
probability that the cost of developing the new ad campaign can be kept within the original
budget allocation is 0.40. Assuming that the two events are independent, the probability that neither the cost is kept within budget nor the campaign will increase sales is:
a)0.12
b)0.32
c)0.68
d)0.88
ANSWER:
a
TYPE: MC DIFFICULTY: Easy
KEYWORDS: statistical independence, multiplication rule, joint probability, complement
34.According to a survey of American households, the probability that the residents own 2 cars if
annual household income is over $25,000 is 80%. Of the households surveyed, 60% had incomes over $25,000 and 70% had 2 cars. The probability that the residents of a household own 2 cars and have an income over $25,000 a year is:
a)0.12
b)0.18
c)0.22
d)0.48
ANSWER:
d
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: joint probability, conditional probability
35.According to a survey of American households, the probability that the residents own 2 cars if
annual household income is over $25,000 is 80%. Of the households surveyed, 60% had incomes over $25,000 and 70% had 2 cars. The probability that the residents of a household do not own 2 cars and have an income over $25,000 a year is:
a)0.12
b)0.18
c)0.22
d)0.48
ANSWER:
a
TYPE: MC DIFFICULTY: Difficult
KEYWORDS: joint probability, complement, multiplication rule, conditional probability
36.According to a survey of American households, the probability that the residents own 2 cars if
annual household income is over $25,000 is 80%. Of the households surveyed, 60% had incomes over $25,000 and 70% had 2 cars. The probability that the residents of a household own 2 cars and have an income less than or equal to $25,000 a year is:
a)0.12
b)0.18
c)0.22
d)0.48
ANSWER:
c
TYPE: MC DIFFICULTY: Difficult
KEYWORDS: joint probability, complement, multiplication rule, conditional probability
37.According to a survey of American households, the probability that the residents own 2 cars if
annual household income is over $25,000 is 80%. Of the households surveyed, 60% had incomes over $25,000 and 70% had 2 cars. The probability that annual household income is over $25,000 if the residents of a household own 2 cars is:
a)0.42
b)0.48
c)0.50
d)0.69
ANSWER:
d
TYPE: MC DIFFICULTY: Difficult
KEYWORDS: conditional probability, Bayes’ theorem
38.According to a survey of American households, the probability that the residents own 2 cars if
annual household income is over $25,000 is 80%. Of the households surveyed, 60% had incomes over $25,000 and 70% had 2 cars. The probability that annual household income is over $25,000 if the residents of a household do not own 2 cars is:
a)0.12
b)0.18
c)0.40
d)0.70
ANSWER:
c
TYPE: MC DIFFICULTY: Difficult
KEYWORDS: conditional probability, complement, Bayes’ theorem
39.According to a survey of American households, the probability that the residents own 2 cars if
annual household income is over $25,000 is 80%. Of the households surveyed, 60% had incomes over $25,000 and 70% had 2 cars. The probability that the residents do not own 2 cars if annual household income is not over $25,000 is:
a)0.12
b)0.18
c)0.45
d)0.70
ANSWER:
c
TYPE: MC DIFFICULTY: Difficult
KEYWORDS: conditional probability, complement
40.A company has 2 machines that produce widgets. An older machine produces 23% defective
widgets, while the new machine produces only 8% defective widgets. In addition, the new
machine produces 3 times as many widgets as the older machine does. Given that a widget was produced by the new machine, what is the probability it is not defective?
a)0.06
b)0.50
c)0.92
d)0.94
ANSWER:
c
TYPE: MC DIFFICULTY: Easy
KEYWORDS: conditional probability, complement
41.A company has 2 machines that produce widgets. An older machine produces 23% defective
widgets, while the new machine produces only 8% defective widgets. In addition, the new
machine produces 3 times as many widgets as the older machine does. What is the probability that a randomly chosen widget produced by the company is defective?
a)0.078
b)0.1175
c)0.156
d)0.310
ANSWER:
b
TYPE: MC DIFFICULTY: Moderate
KEYWORDS: marginal probability
42.A company has 2 machines that produce widgets. An older machine produces 23% defective
widgets, while the new machine produces only 8% defective widgets. In addition, the new
machine produces 3 times as many widgets as the older machine does. Given a randomly chosen widget was tested and found to be defective, what is the probability it was produced by the new machine?
a)0.08
b)0.15
c)0.489
d)0.511
ANSWER:
d
TYPE: MC DIFFICULTY: Difficult
KEYWORDS: conditional probability, Bayes’ theorem
TABLE 4-1
Mothers Against Drunk Driving is a very visible group whose main focus is to educate the public about the harm caused by drunk drivers. A study was recently done that emphasized the problem we all face with drinking and driving. Four hundred accidents that occurred on a Saturday night were analyzed. Two items noted were the number of vehicles involved and whether alcohol played a role in the accident. The numbers are shown below:
Number of Vehicles
Involved
Did alcohol play a role? 1 2 3 Totals
Yes 50 100 20 170
No 25 175 30 230
Totals 75 275 50 400
43.Referring to Table 4-1, what proportion of accidents involved more than one vehicle?
a)50/400 or 12.5%
b)75/400 or 18.75%
c)275/400 or 68.75%
d)325/400 or 81.25%
ANSWER:
d
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, addition rule
44.Referring to Table 4-1, what proportion of accidents involved alcohol and a single vehicle?
a)25/400 or 6.25%
b)50/400 or 12.5%
c)195/400 or 48.75%
d)245/400 or 61.25%
ANSWER:
b
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, joint probability
45.Referring to Table 4-1, what proportion of accidents involved alcohol or a single vehicle?
a)25/400 or 6.25%
b)50/400 or 12.5%
c)195/400 or 48.75%
d)245/400 or 61.25%
ANSWER:
c
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, addition rule
46.Referring to Table 4-1, given alcohol was involved, what proportion of accidents involved a
single vehicle?
a)50/75 or 66.67%
b)50/170 or 29.41%
c)120/170 or 70.59%
d)120/400 or 30%
ANSWER:
b
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, marginal probability
47.Referring to Table 4-1, given that multiple vehicles were involved, what proportion of accidents
involved alcohol?
a)120/170 or 70.59%
b)120/230 or 52.17%
c)120/325 or 36.92%
d)120/400 or 30%
ANSWER:
c
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, conditional probability, addition rule
48.Referring to Table 4-1, given that 3 vehicles were involved, what proportion of accidents
involved alcohol?
a)20/30 or 66.67%
b)20/50 or 40%
c)20/170 or 11.77%
d)20/400 or 5%
ANSWER:
b
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, conditional probability
49.Referring to Table 4-1, given that alcohol was not involved, what proportion of the accidents
were single vehicle?
a)50/75 or 66.67%
b)25/230 or 10.87%
c)50/170 or 29.41%
d)25/75 or 33.33%
ANSWER:
b
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, conditional probability, complement 50.Referring to Table 4-1, given that alcohol was not involved, what proportion of the accidents
were multiple vehicle?
a)50/170 or 29.41%
b)120/170 or 70.59%
c)205/230 or 89.13%
d)25/230 or 10.87%
ANSWER:
c
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, conditional probability, complement
TABLE 4-2
An alcohol awareness task force at a Big-Ten university sampled 200 students after the midterm to ask them whether they went bar hopping the weekend before the midterm or spent the weekend studying, and whether they did well or poorly on the midterm. The following result was obtained.
Did Well on Midterm Did Poorly on Midterm Studying for Exam 80 20
Went Bar Hopping 30 70
51.Referring to Table 4-2, what is the probability that a randomly selected student who went bar
hopping will do well on the midterm?
a.30/100 or 30%
b.30/110 or 27.27%
c.30/200 or 15%
d.(100/200)*(110/200) or 27.50%
ANSWER:
a
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, conditional probability
52.Referring to Table 4-2, what is the probability that a randomly selected student did well on the
midterm or went bar hopping the weekend before the midterm?
a)30/200 or 15%
b)(80+30)/200 or 55%
c)(30+70)/200 or 50%
d)(80+30+70)/200 or 90%
ANSWER:
d
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, addition rule
53.Referring to Table 4-2, what is the probability that a randomly selected student did well on the
midterm and also went bar hopping the weekend before the midterm?
a)30/200 or 15%
b)(80+30)/200 or 55%
c)(30+70)/200 or 50%
d)(80+30+70)/200 or 90%
ANSWER:
a
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, joint probability
54.Referring to Table 4-2, the events "Did Well on Midterm" and "Studying for Exam" are
a)statistically dependent.
b)mutually exclusive.
c)collective exhaustive.
d)None of the above.
ANSWER:
a
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, statistical independence, joint probability
55.Referring to Table 4-2, the events "Did Well on Midterm" and "Studying for Exam" are
a)not statistically dependent.
b)not mutually exclusive.
c)collective exhaustive.
d)None of the above.
ANSWER:
b
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, mutually exclusive, joint probability
56.Referring to Table 4-2, the events "Did Well on Midterm" and "Did Poorly on Midterm" are
a)statistically dependent.
b)mutually exclusive.
c)collective exhaustive.
d)All of the above.
ANSWER:
d
TYPE: MC DIFFICULTY: Easy
KEYWORDS: contingency table, empirical classical probability, statistical independence, mutually exclusive, collective exhaustive, joint probability
57.True or False: When A and B are mutually exclusive, P(A or B) can be found by adding P(A) and
P(B).
ANSWER:
True
TYPE: TF DIFFICULTY: Easy
KEYWORDS: mutually exclusive, addition rule
58.True or False: The collection of all the possible events is called a sample space.
ANSWER:
True
TYPE: TF DIFFICULTY: Easy
KEYWORDS: sample space
59.True or False: If A and B cannot occur at the same time they are called mutually exclusive. ANSWER:
True
TYPE: TF DIFFICULTY: Easy
KEYWORDS: mutually exclusive
60.True or False: If either A or B must occur they are called mutually exclusive. ANSWER:
False
TYPE: TF DIFFICULTY: Easy
KEYWORDS: mutually exclusive, collective exhaustive
61.True or False: If either A or B must occur they are called collectively exhaustive. ANSWER:
True
TYPE: TF DIFFICULTY: Easy
KEYWORDS: collective exhaustive
62.True or False: If P(A) = 0.4 and P(B) = 0.6, then A and B must be collectively exhaustive. ANSWER:
False
TYPE: TF DIFFICULTY: Moderate
KEYWORDS: collective exhaustive, mutually exclusive
63.True or False: If P(A) = 0.4 and P(B) = 0.6, then A and B must be mutually exclusive. ANSWER:
False
TYPE: TF DIFFICULTY: Moderate
KEYWORDS: mutually exclusive
64.True or False: If P(A or B) = 1.0, then A and B must be mutually exclusive. ANSWER:
False
TYPE: TF DIFFICULTY: Moderate
KEYWORDS: mutually exclusive, collective exhaustive
65.True or False: If P(A or B) = 1.0, then A and B must be collectively exhaustive. ANSWER:
True
TYPE: TF DIFFICULTY: Moderate
KEYWORDS: collective exhaustive
66.True or False: If P(A and B) = 0, then A and B must be mutually exclusive.
ANSWER:
True
TYPE: TF DIFFICULTY: Easy
KEYWORDS: mutually exclusive
67.True or False: If P(A and B) = 0, then A and B must be collectively exhaustive.
ANSWER:
False
TYPE: TF DIFFICULTY: Easy
KEYWORDS: collectively exhaustive, mutually exclusive
68.True or False: If P(A and B) = 1, then A and B must be collectively exhaustive.
ANSWER:
True
TYPE: TF DIFFICULTY: Difficult
KEYWORDS: collective exhaustive
69.True or False: If P(A and B) = 1, then A and B must be mutually exclusive.
ANSWER:
False
TYPE: TF DIFFICULTY: Difficult
KEYWORDS: mutually exclusive, collective exhaustive
70.Suppose A and B are independent events where P(A) = 0.4 and P(B) = 0.5. Then P(A and B) =
__________.
ANSWER:
0.2
TYPE: FI DIFFICULTY: Easy
KEYWORDS: statistical independence, multiplication rule
71.Suppose A and B are mutually exclusive events where P(A) = 0.4 and P(B) = 0.5. Then P(A and
B) = __________.
ANSWER:
TYPE: FI DIFFICULTY: Easy
KEYWORDS: mutually exclusive, joint probability, multiplication rule
72.Suppose A and B are mutually exclusive events where P(A) = 0.4 and P(B) = 0.5. Then P(A or B)
= __________.
ANSWER:
0.9
TYPE: FI DIFFICULTY: Easy
KEYWORDS: mutually exclusive, addition rule
73.Suppose A and B are independent events where P(A) = 0.4 and P(B) = 0.5. Then P(A or B) =
__________.
ANSWER:
0.7
TYPE: FI DIFFICULTY: Easy
KEYWORDS: statistical independence, addition rule
74.Suppose A and B are events where P(A) = 0.4, P(B) = 0.5, and P(A and B) = 0.1. Then P(A or B)
= __________.
ANSWER:
0.8
TYPE: FI DIFFICULTY: Easy
KEYWORDS: addition rule
75.Suppose A and B are events where P(A) = 0.4, P(B) = 0.5, and P(A and B) = 0.1. Then P(A|B) =
__________.
ANSWER:
0.2
TYPE: FI DIFFICULTY: Moderate
KEYWORDS: conditional probability
76.Suppose A and B are events where P(A) = 0.4, P(B) = 0.5, and P(A and B) = 0.1. Then P(B|A) =
__________.
ANSWER:
0.25
TYPE: FI DIFFICULTY: Moderate
KEYWORDS: conditional probability
TABLE 4-3
A survey is taken among customers of a fast-food restaurant to determine preference for hamburger or chicken. Of 200 respondents selected, 75 were children and 125 were adults. 120 preferred hamburger and 80 preferred chicken. 55 of the children preferred hamburger.
77.Referring to Table 4-3, the probability that a randomly selected individual is an adult is
__________.
ANSWER:
125/200 or 62.5%
TYPE: FI DIFFICULTY: Moderate
KEYWORDS: empirical classical probability, conditional probability, marginal probability