If the classes of events, and 9 are independent, 21, so are, and 2 3.) Any r.v. X is independent of a degenerate rv. Y. (i) Two disjoint events are independent iff one of them has probability zero. () P(X +1, Y-11-1 for all four pairs of signs, then X and Y are independent r.v.s. 4 Let (4:40), Pla-1.0sis 3 and otherwise Pis defined by additivity. If A. (..1 sis & then each of