1 Assume that E and F are two events with positive probabilities. Show that if P (E|F ) = P (E), then P (F |E) = P (F ).
2 A coin is tossed three times. What is the probability that exactly two heads occur, given that
(a) the first outcome was a head?
(b) the first outcome was a tail?
(c) the first two outcomes were heads?
(d) the first two outcomes were tails?
(e) the first outcome was a head and the third outcome was a head?