For
example, let Y denote the number of heads minus the number of tails for each outcome
of the above sample space S Then
Y(HH) = 2, Y (HT) = 0, Y (TH) = 0, Y (TT) = – 2 Thus, X and Y are two different random variables defined on the same sample
space S Example  22 A person plays a game of tossing a coin thrice