Example 27 Let a pair of dice be thrown and the random variable X be the sum of the
numbers that appear on the two dice Find the mean or expectation of X Solution The sample space of the experiment consists of 36 elementary events in the
form of ordered pairs (xi, yi), where xi = 1, 2, 3, 4, 5, 6 and yi = 1, 2, 3, 4, 5, 6 The random variable X i