- ProbabilityAndStatistics
- FrequencyProbability -- PersonalProbability -- EclecticProbability
- StatisticalRegularity

(These axioms are just the most elementary way to define probabilities. Other axiom schema are used with non-discrete points.)

- Let
**U** be a SeT of discrete points, **e1**,**e2**,**e3**..., called **elementary events**. We call this set, the **universe** or **sample space**.
- Let every elementary event,
**e** in **U**, have a non-negative *weight*, w(**e**), assigned to it.
- Let
**composite events**, Y1,Y2,Y3,... be represented by SubSet*s* of **U**.
- Define the
**probability** of an event **X** (any subset of **U**), as the sum of the weights, w(**e**), for every *elementary event* contained in **X** divided by the sum of the weights of every element of **U**.

[RABeldin]