Probability of an Event and Independent Events. Probability of an Event A measure of the likelihood...
Transcript of Probability of an Event and Independent Events. Probability of an Event A measure of the likelihood...
Probability of an Event and Independent Events
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Probability of an Event
A measure of the likelihood that an event will occur.
Example: What is the probability of selecting a heart from a standard deck of cards?
Number of Desired Outcomesevent
Total Possibe OutcomesP
13
52
10.25 25%
4
Number of Hearts
Total Number of Cards
Independent Events
Two events, A and B, are independent if the fact that A occurs does not affect the probability of B occurring.
When two events, A and B, are independent, the probability of both occurring is:
and P A B P A P B
4 152 6 1
78
Ex: What is the probability of selecting an ace from a standard deck and rolling a 3 on a standard 6-sided die?
4312 Ace 3P P
Selecting a card does not affect rolling a die. They are independent events.
Example
Your teacher challenges you to a spinner game. You spin the two spinners with the probabilities listed below. The first letter should come from Spinner #1 and the second letter from Spinner #2. Find all of the possibilities and the probabilities of each possibility.
T
FI
A
U
12
16
13
P I
P U
P A
14
34
P T
P F
Example: Area Diagram
12
Spinner #1
Spi
nner
#2
IT UT AT
IF UF AF
13
16
14
34
18
112
124
38
14
18
I U A
T
F
124
:Example
P UT
Example: Tree Diagram
12
141
6
START
I
U
A
T
FT
FT
F
14
13
14
34
34
34
1 1 1
2 4 8
1 3 3
2 4 8
1 1 1
6 4 24
1 3 3 1
6 4 24 8
1 1 1
3 4 12
1 3 3 1
3 4 12 4
UT
124
:Example
P UT
1
24