# What is another name for mutually exclusive events?

##### 1 Answer

Another name for mutually exclusive events would be **disjoint** events. Note that **collectively exhaustive** is *not* equivalent to mutual exclusivity, as if a set of events are collectively exhaustive, at least one of the events *must* occur.

As an example, suppose that you roll a fair six sided die once. The event that you roll a 1 is mutually exclusive with the event that you roll a 6; that is, you cannot roll both a 1 and a 6 by rolling the die a single time. However, there exists a possibility that you will roll neither a 1 nor a 6; ergo, the possibilities are not collectively exhaustive.

(As a note, if you consider six events A-F, where A is the event that you roll a 1 on a single roll of the six sided die, B is the event that you roll a 2, C the event that you roll a 3, D the event you roll a 4, E the event you roll a 5, and F the event you roll a 6, then the set of events A-F are both mutually exclusive and collectively exhaustive; you *must* roll one of the numbers on the die when you roll the die.)