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. #For any arbitrary events, A1 and A2, the probability of both events, Pr[A1*A2], is given by the sum of the probabilities of the ''elementary events'' 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, Pr[A1+A2], is given by 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]]