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 © NCERT
not to be republished
 558
MATHEMATICS
(iii)
In the experiment of taking out four articles (one after the other) at random
from a lot of 20 articles in which 6 are defective, we want to know the
number of defectives in the sample of four and not in the particular sequence
of defective and nondefective articles