Definition of

Complement (probability)

Complement (probability)

The Complement of an event is all outcomes that are not the event.

Example: For dice, when the event is {5, 6} the complement is {1, 2, 3, 4}

The symbol is a little dash in the top-right corner
Example: A' = {1, 2, 3, 4}

Together the event and its complement make all possible outcomes.