All these are true when X and Y are independent events:
1) The occurrence or lack of event X does not influence the occurrence of event Y, and the occurrence or lack of event Y does not influence the occurrence of event X.
2) P(X∩Y) = P(X) * P(Y)
3) P(X | Y) = P(X).... this is the probability of X given Y is equal to the probability of X.
4) P (Y | X) = P(Y)
5) P(A∪B) = P(A) + P(B) - P(A∩B)
