A12­7CompoundEventsProb.notebook
January 07, 2013
Algebra 1
Ch.2 Notes Page 40
P40 2­7 Probability of Compound Events
Probability of Independent Events
The result of one does not influence the result of the other.
If A and B are independent events, P(A and B) = P(A) x P(B)
Example: You roll a Red Number Cube and a Blue Number Cube. What is the probability that you will roll a 3 on the Red Cube and an Even on the Blue Cube.
A12­7CompoundEventsProb.notebook
January 07, 2013
Probability of Independent Events
3 Blue
2 Red
5 Green
10 Total
Bag of Marbles
*With Replacement
P(Blue and Red)
Probability of Independent Events
In a word game, you choose a tile at random from a bag containing the letter tiles shown. You replace the first tile and then choose again. What is the probability that you will choose an A and then an E?
15 Tiles
P(A and E)
A12­7CompoundEventsProb.notebook
January 07, 2013
Probability of Dependent Events
The result of one does influence the result of the other.
If A and B are dependent events,
P(A then B) = P(A) x P(B after A)
3 Blue
2 Red
5 Green
10 Total
Bag of Marbles
*Without Replacement
P(Blue then Red)
Probability of Dependent Events
15 Tiles *Without Replacement
You take a tile at random from the tiles shown. Without replacing the tile, you select a second tile. What is the probability that you will choose an A and then an E?
P(A then E)
A12­7CompoundEventsProb.notebook
January 07, 2013