Event

Study guide: Exam P-1

An event E is any subset of the Sample Space S.

• Events are the objects to which probabilities are assigned.
• A simple (elementary) event contains exactly one outcome.
• The Axioms of Probability define P(E) \in [0,1] for every event E, with P(S) = 1.

Rolling a Die A fair six-sided die is rolled. The sample space is S = \{1,2,3,4,5,6\}.

Answer Let E = \{2, 4, 6\} be the event "an even number is rolled." This event contains 3 outcomes. P(E) = \frac{|E|}{|S|} = \frac{3}{6} = 0.5