Statistics for Maintenance Modelling: Basic Probability Concepts

# Axioms of Probability¤

In order for the definition of probability to be valid, certain assumptions or axioms must be held true. These axioms are more or less intuitive, and state that:

## Axiom 1:

0 P(E) 1

The probability of event E is some number between 0 and 1.

## Axiom 2:

P(S) = 1

The outcome will be a point in the sample space with probability 1.

## Axiom 3

For any sequence of mutually exclusive events E1, E2 …

The probability of at least one of these mutually exclusive events occurring is just the sum of their respective probabilities. Click here for an example.