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COURSE 2 LESSON 12-4
Sample Spaces
a. Make a table to show the sample space for tossing two coins. Write the
outcomes as ordered pairs.
H
T
H (H,H)
(H,T )
T (T ,H)
(T ,T )
There are 4 possible outcomes.
b. Find P(T, T), the probability of tossing two tails.
There is one outcome for tossing two tails. There are four possible
outcomes. So the probability of tossing two tails is 1 .
4
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COURSE 2 LESSON 12-4
Sample Spaces
Suppose you can go west or northwest by train, bus, or car.
a. Draw a tree diagram to show the sample space.
Vehicle
Train
Bus
Car
Direction
Outcomes
West
Train, West
Northwest
Train, Northwest
West
Bus, West
Northwest
Bus, Northwest
West
Car, West
Northwest
Car, Northwest
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There are 6 possible
outcomes.
COURSE 2 LESSON 12-4
Sample Spaces
(continued)
b. What is the probability of a random selection that results in a
bus trip west?
Vehicle
Train
Bus
Car
Direction
Outcomes
West
Train, West
Northwest
Train, Northwest
West
Bus, West
Northwest
Bus, Northwest
West
Car, West
Northwest
Car, Northwest
There is one favorable outcome (bus, west) out of six possible outcomes.
The probability is 1 .
6
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COURSE 2 LESSON 12-4
Sample Spaces
How many kinds of coin purses are available if the purses come
in small or large sizes and colors red, blue, yellow, and black?
Sizes
small
large
Colors
red
blue
yellow
black
Use the counting principle.
Size
number of choices
2


Color
number of choices
4
=8
There are 8 different kinds of coin purses available.
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COURSE 2 LESSON 12-4
Sample Spaces
You pick a card at random from cards labeled 1, 2, or 3 and then spin a
spinner divided into thirds, each of which is labeled with numbers 1, 2, or 3.
1. Make a table showing the
sample space.
1
2
3
1
2
3
(1, 1) (2, 1) (3, 1)
(1, 2) (2, 2) (3, 2)
(1, 3) (2, 3) (3, 3)
2. How many possible outcomes are there?
9
3. What is the probability of two 3s?
1
9
4. What is the probability of picking a card and spinning the
same number?
1
3
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