Example 5.3. An experiment on rabbits is designed by taking N = 20 identical rabbits. But rabbits start dying out before the experiment is completed. Let n be the effective final number. This sample size n has become a random quantity. n could be zero (all rabbits died out), n could be 1,2,... and could be N = 20 (no rabbit died). Let 0.1 be the probability of a rabbit dying and suppose that this probability is the same for all rabbits. Construct the probability law for n.