1.4 Complementary Events

Venn diagrams can be a useful way of visualising a sample space. Below can be seen which equally-likely outcomes of the roll of a die are square numbers, and which are not.

The event \(\textbf{not A}\), often notated as \(\overline{\mathbf{A}}\) or \(\mathbf{A'}\), is called the \(\textbf{complement of }\mathbf{A}\).