9.2 Connecting Probability to Models and Counting

Remember to Silence Your Cell Phone and Put It In Your Bag!

Counting TheoryTree Diagram

The Fundamental Counting Principle If event A has m outcomes and event

B has n outcomes, then the experiment that has event A followed by event B has m × n outcomes.

Property may be generalized to more than two events

Probability ofIndependent Events

Independent Events When the outcome of one event has no

influence on the outcome of a second event When knowing whether A occurs does not

change the probability that B occurs

Multiplication Property of Probabilities Involving Independent Events If events A and B are independent, then

P(A and B) = P(A) × P(B).

For all multistage experiments, the probability of the outcome along any path of a tree diagram is equal to the product of all the probabilities along the path.

Conditional Probability Omit pp. 512-514