Wikipedia 10K Redux by Reagle from Starling archive. Bugs abound!!!
:[[Probability]] :[[Probability Axioms]] -- [[Probability Distributions]] The basic theorems of probability can be developed easily from the [[Probability Axioms]] and [[Set Theory]]. #The sum of the probabilities for all the ''elementary events'' is one. *SUM Pr[Ei] = 1 #For any arbitrary events, A1 and A2, the probability of both events, *Pr[A1*A2] = SUM of Pr[Ei] for all Ei in both A1 and A2. If the intersection is empty, then the probability is exactly zero. #For any arbitrary events, A1 and A2, the probability of either or both, , is given by * Pr[A1+A2] = Pr[A1] + Pr[A2] - Pr[A1*A2] The probability of some event happening knowning that some other one happened before can be computed using [[Conditional Probability]]. ---- [[Dick Beldin]]