#### Review of Probability

The probability of an event is determined by the following formula:

P(E)= #Success/Possible outcomes

For example, the probability when rolling a fair die and getting a 6 is:

P(6)= 1/6

That is there is 1 success with 6 outcomes

The probability of an event not happening is:

P(not happening) = 1 - P(E)

The probability of rolling a fair die and not getting a 6 is:

P(not 6) = 1- (1/6)= 5/6

Probability of mutually exclusive events

Two events are mutually exclusive when they can NOT happen at the same time

For example:

When I rolled a die, either you get a 2 or a 3

When you toss a coin, you either get heads or tails

The formula for mutually exclusive events is:

P(A or B) = P(A) + P(B)