Event

Definition

An event is one or more outcomes of a probability experiment.

Often the letter "E" represents an event.
P(E) represents the probability that event E will occur.
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 then event "B".

Example

In an experiment of tossing a die, there are six possible outcomes.

A listing of all of the outcomes of an experiment is called the sample space (S) of the experiment.

If each face is represented by a numeral of the number of dots on the face; the following represents the sample space for this experiment:

S: { 1, 2, 3, 4, 5, 6 }

Any of the six outcomes is an event. Note that groups of outcomes can also be an event. Some examples are given below:

Event Q: Getting a 1 or a 2.

Event R: Getting an even number (2 or 4 or 6).

Event S: Getting a 3.

Event T: Getting a 1, 2, 3, 4, 5 or 6.

Image only

Instructions text as in global.js

If n(S) represents the number of outcomes in the sample space [n(S) = 6] and n(E) represents the number of outcomes in event E, then: