Therefore, calculation of probabilities of 0, 1, 2, ,
n number of successes may be lengthy and time consuming To avoid the lengthy
calculations and listing of all the possible cases, for the probabilities  of number of
successes in n-Bernoulli trials, a formula is derived For this purpose, let us take the
experiment made up of three Bernoulli trials with probabilities p and q = 1 – p for
success and failure respectively in each trial