5-12 Chapter 5 Randomness and Probability
5.3.2 Find probabilities and/or determine independence.
3. During a promotion, Christina’s department store offers a mailing “scratch a winner –
discount savings.” After customers select the items they wish to purchase, they scratch
their discount sticker from the mailing to determine the discount they will receive. The
scratch wheel is divided into 12 slices. Six slices are red and award a 10% discount,
three slices are white and award a 20% discount, and two slices are blue and award a 40%
discount. The remaining slice is gold and awards a 100% discount if the customer
scratches that slice! The probability that two customers in a row get a 20% discount is
A. 3/12
B. 2/12
C. .0625
D. 9/12
E. 10/12
5.3.2 Find probabilities and/or determine independence.
4. A recent survey of local cell phone retailers showed that of all cell phones sold last
month, 64% had a camera, 28% had a music player and 22% had both. The probability
that a cell phone sold last month had a camera or a music player is
A. .22
B. .70
C. .92
D. .30
E. .08
5.3.2 Find probabilities and/or determine independence.
5. A recent survey of local cell phone retailers showed that of all cell phones sold last
month, 64% had a camera, 28% had a music player and 22% had both. The probability
that a cell phone sold last month did not have either a camera or a music player is
A. .22
B. .70
C. .92
D. .30
E. .08
Quiz C 5-13
5.3.2 Find probabilities and/or determine independence.
6. A recent survey of local cell phone retailers showed that of all cell phones sold last
month, 64% had a camera, 28% had a music player and 22% had both. Which of the
following statements about cell phones sold last month is true?
A. Having a camera and having a music player are mutually exclusive events.
B. The intersection of having a camera and having a music player is zero.
C. Having a camera and having a music player are independent events.
D. Having a camera and having a music player are disjoint events.
E. Having a camera and having a music player are not mutually exclusive events.
5.5.2 Find probabilities and/or determine independence.
7. The option to buy extended warranties is commonplace with most electronics
purchases. But does the type of purchase affect a consumer’s willingness to pay extra for
an extended warranty? Data for 420 consumers who purchased digital cameras and
laptop computers from a leading electronics retailer are summarized in the table. The
probability that a consumer does not purchase an extended warranty is
A. .07
B. .42
C. .58
D. .17
E. .83
Purchased Warranty?
Yes No Total
Digital Camera 30 42 72
Laptop Computer 145 203 348
Total 175 245 420
5-14 Chapter 5 Randomness and Probability
5.5.2 Find probabilities and/or determine independence.
8. The option to buy extended warranties is commonplace with most electronics
purchases. But does the type of purchase affect a consumer’s willingness to pay extra for
an extended warranty? Data for 420 consumers who purchased digital cameras and
laptop computers from a leading electronics retailer are summarized in the table. The
probability that a consumer purchases a digital camera and an extended warranty is
A. .07
B. .42
C. .58
D. .17
E. .83
5.5.2 Find probabilities and/or determine independence.
9. The option to buy extended warranties is commonplace with most electronics
purchases. But does the type of purchase affect a consumer’s willingness to pay extra for
an extended warranty? Data for 420 consumers who purchased digital cameras and
laptop computers from a leading electronics retailer are summarized in the table. The
probability that a consumer purchases an extended warranty given that he/she has
purchased a digital camera is
A. .07
B. .42
C. .58
D. .17
E. .83
Purchased Warranty?
Yes No Total
Digital Camera 30 42 72
Laptop Computer 145 203 348
Total 175 245 420
Purchased Warranty?
Yes No Total
Digital Camera 30 42 72
Laptop Computer 145 203 348
Total 175 245 420
Quiz C 5-15
5.5.2 Find probabilities and/or determine independence.
10. The option to buy extended warranties is commonplace with most electronics
purchases. But does the type of purchase affect a consumer’s willingness to pay extra for
an extended warranty? Data for 420 consumers who purchased big screen TVs and
laptop computers from a leading electronics retailer are summarized in the table. Which
of the following statement is true?
A. The decision to purchase an extended warranty and type of electronics (big screen TV
or laptop computer) purchased are independent.
B. The decision to purchase an extended warranty and type of electronics (big screen TV
or laptop computer) purchased are mutually exclusive.
C. The decision to purchase an extended warranty and type of electronics (big screen TV
or laptop computer) purchased are disjoint events.
D. The decision to purchase an extended warranty and type of electronics (big screen TV
or laptop computer) purchased are not independent.
E. The decision to purchase an extended warranty and type of electronics (big screen TV
or laptop computer) purchased are related.
5.3.2 Find probabilities and/or determine independence.
11. As accounts manager in your company, you classify 75% of your customers as “good
credit” and the rest as “risky credit” depending on their credit rating. Customers in the
“risky” category allow their accounts to go overdue 50% of the time on average, whereas
those in the “good” category allow their accounts to become overdue only 10% of the
time. What percentage of overdue accounts are held by customers in the “risky credit”
category?
A. 20%
B. 12.5%
C. 93.75%
D. 62.5%
Purchased Warranty?
Yes No Total
Big Screen TV 30 42 72
Laptop Computer 145 203 348
Total 175 245 420
5-16 Chapter 5 Randomness and Probability
Chapter 5: Randomness and Probability – Quiz C – Key
Quiz D 5-17
Chapter 5: Randomness and Probability – Quiz D – Multiple Choice
Name_____________________________________
5.4.1 Find probabilities and/or determine independence.
1. As an incentive to get new customers, the local branch of a bank launched “bouncing
for bucks.” During this week long event, any customer opening a new checking account
with the bank would have the opportunity to throw a bouncy rubber ball into a large box
divided into squares. Each square was labeled with a dollar amount that would be
deposited into his/her new checking account. The way the box was labeled is shown
below. What is the probability that a customer gets $50?
10 30 10 30 10
20 10 50 10 20
A. 0.10
B. 0.01
C. 0.50
D. 0.05
E. 0.20
5.4.1 Find probabilities and/or determine independence.
2. As an incentive to get new customers, the local branch of a bank launched “bouncing
for bucks.” During this week long event, any customer opening a new checking account
with the bank would have the opportunity to throw a bouncy rubber ball into a large box
divided into squares. Each square was labeled with a dollar amount that would be
deposited into his/her new checking account. The way the box was labeled is shown
below. What is the probability that a customer does not get $50?
10 30 10 30 10
20 10 50 10 20
A. 0.90
B. 0.99
C. 0.50
D. 0.95
E. 0.80
5-18 Chapter 5 Randomness and Probability
5.4.1 Find probabilities and/or determine independence.
3. As an incentive to get new customers, the local branch of a bank launched “bouncing
for bucks.” During this week long event, any customer opening a new checking account
with the bank would have the opportunity to throw a bouncy rubber ball into a large box
divided into squares. Each square was labeled with a dollar amount that would be
deposited into his/her new checking account. The way the box was labeled is shown
below. What is the probability that three customers in a row do not get $50?
10 30 10 30 10
20 10 50 10 20
A. 0.125
B. 0.001
C. 0.729
D. 0.970
E. 0.300
5.4.1 Find probabilities and/or determine independence.
4. As an incentive to get new customers, the local branch of a bank launched “bouncing
for bucks.” During this week long event, any customer opening a new checking account
with the bank would have the opportunity to throw a bouncy rubber ball into a large box
divided into squares. Each square was labeled with a dollar amount that would be
deposited into his/her new checking account. The way the box was labeled is shown
below. Out of the next three customers that come into the bank and play the game, what
is the probability that at least one gets $50?
10 30 10 30 10
20 10 50 10 20
A. 0.001
B. 0.271
C. 0.729
D. 0.300
E. 0.125
5.4.1 Find probabilities and/or determine independence.
5. It has been reported that men are more likely than women to participate in online
auctions. In a recent survey, 65% of respondents reported that they had participated in an
online auction. In this same survey, 45% of respondents were men and 38% were men
who had participated in online auctions. Which of the following is true?
A. Gender and participation in online auctions are independent.
B. Gender and participation in online auctions are disjoint.
C. The intersection of being male and participating in online auctions is zero.
D. Gender and participation in online auctions are not related.
E. Gender and participation in online auctions are dependent.
Quiz D 5-19
5.4.1 Find probabilities and/or determine independence.
6. It has been reported that men are more likely than women to participate in online
auctions. In a recent survey, 65% of respondents reported that they had participated in an
online auction. In this same survey, 45% of respondents were men and 38% were men
who had participated in online auctions. What is the probability that a respondent
selected at random is female and has never participated in an online auction?
A. 0.62
B. 0.72
C. 0.38
D. 0.28
E. 0.07
5.4.1 Find probabilities and/or determine independence.
7. It has been reported that men are more likely than women to participate in online
auctions. In a recent survey, 65% of respondents reported that they had participated in an
online auction. In this same survey, 45% of respondents were men and 38% were men
who had participated in online auctions. What is the probability that a respondent had
participated in an online auction given that he is male?
A. 0.38
B. 0.84
C. 0.62
D. 0.45
E. 0.55
5.3.2 Use and understand the concepts and definitions of probability.
8. Suncast Cable offers high definition (HD) cable TV, Internet and phone services to its
customers. For those service issues that can be resolved by calling its technical support
center, Suncast’s goal is to have the problem solved within 30 minutes. In order to
determine how well it is achieving this goal, they monitored calls to its technical support
center over the last three months. The data compiled is shown in the table below. If
Suncast wished to determine probabilities using these data, what type of probability
would it be calculating?
Problem Resolved? HD cable TV Internet Phone
Yes 123 350 77
No 115 122 63
A. Personal
B. Theoretical
C. Empirical
D. Model-based
E. Subjective
5-20 Chapter 5 Randomness and Probability
5.3.2 Use and understand the concepts and definitions of probability.
9. Suncast Cable offers high definition (HD) cable TV, Internet and phone services to its
customers. For those service issues that can be resolved by calling its technical support
center, Suncast’s goal is to have the problem solved within 30 minutes. In order to
determine how well it is achieving this goal, they monitored calls to its technical support
center over the last three months. The data compiled is shown in the table below. What
is the probability that a call to the technical support center involved an issue with Internet
service?
Problem Resolved? HD cable TV Internet Phone
Yes 123 350 77
No 115 122 63
A. 0.56
B. 0.41
C. 0.74
D. 0.26
E. 0.35
5.3.2 Use and understand the concepts and definitions of probability.
10. Suncast Cable offers high definition (HD) cable TV, Internet and phone services to
its customers. For those service issues that can be resolved by calling its technical
support center, Suncast’s goal is to have the problem solved within 30 minutes. In order
to determine how well it is achieving this goal, they monitored calls to its technical
support center over the last three months. The data compiled is shown in the table below.
What is the probability that a call to the technical support center involved an issue with
Internet service or was not resolved within 30 minutes?
Problem Resolved? HD cable TV Internet Phone
Yes 123 350 77
No 115 122 63
A. 0.91
B. 0.55
C. 0.35
D. 0.76
E. 0.14
Quiz D 5-21
5.8.3 Construct and use probability trees.
11. A manufacturer claims that its drug test will detect steroid use (that is, show positive
for an athlete who uses steroids) 95% of the time. Further, 15% of all steroid-free
individuals also test positive. 10% of the rugby team members use steroids. Your friend
on the rugby team has just tested positive. The correct probability tree looks like
5.8.3 Construct and use probability trees.
12. A manufacturer claims that its drug test will detect steroid use (that is, show positive
for an athlete who uses steroids) 95% of the time. Further, 15% of all steroid-free
individuals also test positive. 10% of the rugby team members use steroids. Your friend
on the rugby team has just tested positive. The probability that he uses steroids is
A. 0.4130
B. 0.8636
C. 0.0950
D. 0.2300
5-22 Chapter 5 Randomness and Probability
Chapter 5: Randomness and Probability – Quiz D – Key