6  Random Variables and its Probability Distributions
We have already learnt about random experiments and formation of sample spaces In
most of these experiments, we were not only interested in the particular outcome that
occurs but rather in some number associated with that outcomes  as shown in following
examples/experiments (i)
In tossing two dice, we may be interested in the sum of the numbers on the
two dice (ii)
In tossing a coin 50 times, we may want the number of heads obtained