In
probability theory and
statistics, the geometric distribution is either of two
discrete probability distributions:the probability distribution of the number X of
Bernoulli trials needed to get one success, supported on the set { 1, 2, 3, ...}, orthe probability distribution of the number Y = X − 1 of failures before the first success, supported on the set { 0, 1, 2, 3, ... }.
See more at Wikipedia.org...
The geometric distribution (the term first used by Feller, 1950) is defined as:
f(x) = p*(1-p)x
where
n is the probability that a particular event (e.g., success) will occur