Name
LESSON
Date
Class
Practice A
8-7 Making Predictions
Use the sample survey to make predictions.
Favorite Pets
1. If you randomly selected a person,
what is the probability that his or her
favorite pet is a cat?
2. In a group of 50 people, how many
do you predict would choose a dog
as their favorite pet?
Pet
Number of
Students
Dog
15
Cat
10
Bird
8
Hamster
5
Fish
5
Other
7
3. In a class of 20 students, how many
students do you predict would choose
a hamster as their favorite pet?
4. In a group of 100 people, how many do you predict would
choose a bird as their favorite pet?
5. A toothpaste company claims that 90% of all dentists surveyed
recommend its brand. If you randomly selected 10 dentists, how
many do you predict would recommend that brand of
toothpaste?
6. If you flip a coin 60 times, how many times do you predict it
would land heads up?
7. Based on a sample survey, a pizza restaurant claims that 85%
of its pizzas are delivered in less than 30 minutes. If the
restaurant delivers 200 pizzas Friday night, how many do you
predict will be delivered in less than 30 minutes?
8. If you roll a standard number cube 12 times, how many times do
you predict it would land on 4?
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Holt Mathematics
Practice B
8-7 Making Predictions
Practice A
8-7 Making Predictions
LESSON
LESSON
Use the sample survey to make predictions.
Use the sample survey to make predictions.
Favorite Pets
1. If you randomly selected a person,
what is the probability that his or her
favorite pet is a cat?
1
5
2. In a group of 50 people, how many
do you predict would choose a dog
as their favorite pet?
15 people
Pet
Number of
Students
Dog
15
Cat
10
Bird
8
Hamster
5
Fish
5
Other
7
1. If you randomly selected a person,
what is the probability that his or her
favorite sport is basketball?
Number of
Students
Sport
7
30
2. In a group of 200 people, how many
do you predict would choose baseball
as their favorite sport?
60 people
3. In a class of 45 students, how many
students do you predict would choose
soccer as their favorite sport?
3. In a class of 20 students, how many
students do you predict would choose
a hamster as their favorite pet?
Football
28
Basketball
35
Soccer
20
Baseball
45
Hockey
15
Other
7
6 students
2 students
4. In a group of 100 people, how many do you predict would
choose hockey as their favorite sport?
4. In a group of 100 people, how many do you predict would
choose a bird as their favorite pet?
10 people
16 people
5. Based on a sample survey, a local newspaper states that 75%
of all the city’s voters turned out for the city council elections. If
you randomly selected 200 people in that city, how many do you
predict would have voted in the election?
5. A toothpaste company claims that 90% of all dentists surveyed
recommend its brand. If you randomly selected 10 dentists, how
many do you predict would recommend that brand of
toothpaste?
150 people
9 dentists
6. If you roll a fair number cube 30 times, how many times would
you expect to roll an odd number?
6. If you flip a coin 60 times, how many times do you predict it
would land heads up?
15 times
30 times
7. Based on a sample survey, a company claims that 8% of its
customers were unhappy with the DVD players they bought. If the
company sold DVD players to 2,000 people last year, how many of
those customers do you predict were unhappy with their DVDs?
7. Based on a sample survey, a pizza restaurant claims that 85%
of its pizzas are delivered in less than 30 minutes. If the
restaurant delivers 200 pizzas Friday night, how many do you
predict will be delivered in less than 30 minutes?
160 customers
170 pizzas
8. If you toss a fair coin 48 times, how many times do you predict it
will land tails up?
8. If you roll a standard number cube 12 times, how many times do
you predict it would land on 4?
24 times
two times
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Favorite Sports
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Holt Mathematics
58
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Mathematics
Review for Mastery
8-7 Making Predictions
Practice C
8-7 Making Predictions
LESSON
LESSON
A prediction is a guess about something in the future. You can use
theoretical probability to make predictions.
Use the sample survey to make predictions.
1. If you randomly selected a person, what is
the probability that his or her favorite color
is yellow or purple?
4
25
2. In a group of 4,500 people, how many do
you predict would choose blue as their
favorite color?
1,410 people
Favorite Color
Color
Number of
Students
Blue
94
Red
85
Green
60
Purple
36
Yellow
12
Other
13
1
2
6
3
5
4
Look at the spinner above. To find the number of times you expect to
land on a composite number in 27 spins, first find the theoretical
probability of the event.
3. In a school of 600 students, how many
students do you predict would choose
red or green as their favorite color?
2
1
P(composite number) 6 3
This means that the spinner will land on a composite number about
1
of the time.
3
290 students
4. In a group of 100 people, how many do you predict would not
choose yellow as their favorite color?
Then multiply the theoretical probability by the number of times that
you carry out the experiment.
1
Find 3 of 27 times.
96 people
1
27
3
27
3
5. Based on a sample survey, a local newspaper claims that 79%
of its daily papers are printed on recycled paper. If the
newspaper uses 5,000 tons of paper to print its daily paper, how
much of that do you predict is recycled paper?
9
You can predict that the spinner will land on a composite number
about 9 times in 27 spins.
3,950 tons
6. Carol flips a fair coin and rolls a standard number cube 40 times
each. How many times do you predict the outcome will be heads
up and a prime number?
Look at the spinner above. Use theoretical probability to make
a prediction.
10 times
1. Landing on an odd number in 42 spins.
7. In a sample of 350 video games, a company found that 24 were
defective. If the company manufactures 15,000 of those games
each year, about how many of them do you predict will be
defective?
21 times
2. Landing on a number that is neither prime nor composite in
30 spins.
5 times
about 1,029 games
3. Landing on a number that is less than 5 in 18 spins.
12 times
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59
Copyright © by Holt, Rinehart and Winston.
Holt Mathematics
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
85
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Holt Mathematics