mutually exclusive event

statistics

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 1, 2026

Quick Summary

In statistics, mutually exclusive events are occurrences that cannot happen at the same time. If one event takes place, the other event is impossible. For example, when flipping a coin, getting heads and getting tails are mutually exclusive events because only one can occur on a single flip.12

This concept is fundamental in probability theory. When events are mutually exclusive, the probability of either one occurring is the sum of their individual probabilities. The term "mutually exclusive" means that each event precludes the other.23

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

5 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

statistics
Events and their probabilities
…events are said to be mutually exclusive if the occurrence of one event means that the other event cannot occur; in this case, when one event takes place, the probability of the other event occurring is zero.
Read More
…events are said to be mutually exclusive if the occurrence of one event means that the other event cannot occur; in this case, when one event takes place, the probability of the other event occurring is zero.
Read More