In mathematics, the Bernoulli distribution, named after Swiss scientist James Bernoulli, is a discrete probability distribution, which takes value 1 with success probability p and value 0 with failure probability q = 1 − p. The probability mass function f of this distribution is
The expected value of a Bernoulli random variable is p, and its variance is
- pq = p(1 − p).
The Bernoulli distribution is a member of the exponential family.
See also Bernoulli trial, Bernoulli process.