The Bernoulli distribution is the probability discrete distribution of a random variable which takes value 1 with success probability p and value 0 with failure probability q = 1 - p. It can be used, for example, to represent the toss of a coin, where "1" is defined to mean "heads" and "0" is defined to mean "tails" (or vice versa). It is a special case of a Binomial Distribution where n = 1.