geometric distribution the geometric distribution is a negative binomial distribution where r is 1. It is useful for modeling the runs of consecutive successes (or failures) in repeated independent trials of a system. The geometric distribution models the number of successes before one failure in an independent succession of tests where each test results in success or failure. The geometric distribution with prob = p has density p(x) = p (1-p)^x for x = 0, 1, 2, …, 0 < p ≤ 1. If an element of x is not integer, the result of dgeom is zero, with a warning. The quantile is defined as the smallest value x such that F(x) ≥ p, where F is the distribution function. negative binomial distribution