Statistics Toolbox

nbincdf

Negative binomial cumulative distribution function.

Syntax

Y = nbincdf(X,R,P)

Description

Y = nbincdf(X,R,P) computes the negative binomial cdf at each of the values in X using the corresponding parameters in R and P. Vector or matrix inputs for X, R, and P must have the same size, which is also the size of Y. A scalar input for X, R, or P is expanded to a constant matrix with the same dimensions as the other inputs.

The negative binomial cdf is

The motivation for the negative binomial is the case of successive trials, each having a constant probability P of success. What you want to find out is how many extra trials you must do to observe a given number R of successes.

Example

x = (0:15);
p = nbincdf(x,3,0.5);
stairs(x,p)

See Also
cdf, nbininv, nbinpdf, nbinrnd, nbinstat

nansum

nbininv