Transcript Chapter 9 Section 1

Chapter 9 Section 1
Probability Review
Probability Review
Fraction
1. ¼
Decimal
Percent
.25
25%
2. 2/7
.2857
28.6%
3. 1
1
100%
Probability -How likely it is that an event
will occur
Vocabulary

Theoretical Probability

What “should” happen, mathematically
P(E) =
# of favorable outcomes
# of total possible outcomes
More Vocabulary
• Trials
• Each time an experiment is performed
•Outcomes
•Results of the trials
•Experimental Probability
•Found by actually observing an
experiment
•(what really happened)
P(E) =
# of favorable outcomes
# of total possible outcomes
Ex. 1 What is the probability of
rolling a 6 on a die?
P(6)=
1
6
Ex. 2 Out of 1100 people, 836 played a
sport. What is the probability that a
person picked at random will play a
sport?
P(play a sport)=
836 = 19/25
1100
Sample Space:

The set of all possible outcomes of an
experiment
How to find a sample space:
Tree Diagram
 Draw a tree
diagram to show
the sample space
of flipping a coin
and then rolling a
6-sided die.
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H
T
1
2
3
4
5
6
1
2
3
4
5
6
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H1
H2
H3
H4
H5
H6
T1
T2
T3
T4
T5
T6
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12
possibilities!!!
Ex. 3 A person flips a penny, a nickel and a
dime. Find the probability that EXACTLY 2 of
the coins landed on heads?
H
H
H
HHH
T
HHT
H
HTH
T
HTT
H
THH
T
H
T
T THT
H
TTH
T
TTT
T
P(exactly 2 heads)=
= 3
8
Ex. 4 Suppose a coin is flipped 100
times, Predict how many time you will roll
a heads.
1
P(heads)=
2
½ of 100  ½(100)= 50