Definition 1.2.1. The following are probability terms used:

1.

Random experiment: (also called act, trial, operation, or process) is an activity that leads to the occurrence of one and only one of several possible outcomes which is not likely to be known until its completion.

2.

Experiment: Refers to the process of obtaining an observed result of some phenomenon, tossing a coin.

3.

Outcome: A possible result of an experiment (e.g., getting a 4 on a die roll).

Only one of the possible outcomes will occur at any given trial of the experiment.

4.

Sample Space \(S\): Refers to a set of all possible outcomes of an experiment and denoted by \(S\). (e.g., for a die, \(S = \{1, 2, 3, 4, 5, 6\})\).

5.

Event \(E\): A subset of a sample space is called and event. (e.g., rolling an even number, \(E=\{2,4,6\})\).

(a)

Events \(A_1, A_2, A_3,\cdots , A_n\) are said to be mutually exclusive, if \(A_j\cap A_i=\emptyset \) then \(i\neq j\).

(b)

Two or more events are said to be equally likely if each has an equal chance to occur.

(c)

Two events are said to be independent if the occurrence of one does not affect the other.