Event

Topics: Probability

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(definition)

An event is a subset of a sample space $\Omega$, where we can say whether an experiment is done or not.

Events are denoted by uppercase letters of the Latin alphabet:

$$A,B,C,D,E,\cdots \subseteq \Omega$$

Types §

Let $A$ and $B$ be two events. We say that:

• $A$ is an impossible event if $A=\varnothing$
• $A$ is certain if $A=\Omega$
• $A$ and $B$ occur if $A\cap B$
• $A$ or $B$ occur if $A\cup B$
• $A$ occurring implies that $B$ occurs if $B\subseteq A$
• $A$ and $B$ are disjoint or mutually exclusive events if $A\cup B=\varnothing$