Parameters for negbinomial Function?

[mark4flies]

They share a common basis: the Bernoulli trial. The binomial distribution is for n independent Bernoulli trials, each with the same probability of success p. The PMF is the probability of y successes given n trials and p.

The negbinomial distribution is for the number of successes in a sequence of independent and identically distributed Bernoulli trials before a specified (non-random) number of failures occurs. This distribution is useful in QA work, for example.

Similar names but the negbinomial distribution is related more closely with the geometric and hypergeometric distributions than it is the binomial distribution.

With both distributions, 'success' and 'failure' can be substituted with any dichotomous outcomes or switched.