A bag contains seven balls that are numbered consecutively from 2 to 8. The random variable X is the number of even-numbered balls that are selected when two balls are taken at random from the bag. a) Draw up the probability distribution table for X.
b) Find E(X) and Var(X).
c) The random variable Y is the number of odd-numbered balls selected. Show that E(Y) and E(X) are different, but that Var(Y) and Var(X) are identical