Probability (of an event)

Definition

In an experiment, the probability of an event is the likelihood of that event occuring.

Probability is a value between (and including) zero and one.

If P(E) represents the probability of an event E, then:

- P(E) = 0 if and only if E is an impossible event.
- P(E) = 1 if and only if E is an certain event.
- 0 ≤ P(E) ≤ 1.
- Given the two events "A" and "B", P(A) > P(B) if and only if event "A" is more likely to occur the event "B".

A listing of all of the outcomes of an experiment is called the sample space (S) of the experiment and n(S) represents the number of outcomes in the sample space.

If n(E) represents the number of outcomes in event E, then:

More

An experimental probability is measured.

A theoretical probability is calculated.