- 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**.