- P(A,B) = P(A|B)P(B) = P(B|A)P(A)^ probability of "A and B"This is always true.You can easily get Bayes rule by moving one factor under the other side.Bayes rule allows one to calculate "B given A" when we are given "A given B", ie, it allows to
*reverse*the direction of a conditional probability.KY