Complement of an Event
Consider the experiment of rolling a single die.
. Let be the event that the roll yields a number greater than . . Then .
Remember: . , so . Since and are mutually exclusive , . Therefore,
When it is not raining, the probability of the New Orleans Saints winning a football game is . What is the probability of the Saints winning if it is raining?
(Saints winning with rain)
= (Saints winning without rain)