Mutually exclusive events

Summary

Definition

• Two events are said to be mutually exclusive if they have no elements (outcome) in common (they cannot both be true).

Example

• Dice with $S={1,2,3,4,5,6}$ . $A={1,2,3}$ and $B={4,5}$ are mutually exclusive events while $C={1,2,3}$ and $D={3,4,5}$ are not.

Example

• $A$ and $B$ are mutually exclusive events if and only if $A∩B=∅$ .