nbinrnd (Statistics Toolbox)

Random matrices from a negative binomial distribution

Syntax

RND = nbinrnd(R,P)
RND = nbinrnd(R,P,m)
RND = nbinrnd(R,P,m,n)

Description

RND = nbinrnd(R,P) is a matrix of random numbers chosen from a negative binomial distribution with parameters R and P. Vector or matrix inputs for R and P must have the same size, which is also the size of RND. A scalar input for R or P is expanded to a constant matrix with the same dimensions as the other input.

RND = nbinrnd(R,P,m) generates random numbers with parameters R and P, where m is a 1-by-2 vector that contains the row and column dimensions of RND.

RND = nbinrnd(R,P,m,n) generates random numbers with parameters R and P, where scalars m and n are the row and column dimensions of RND.

The simplest motivation for the negative binomial is the case of successive random trials, each having a constant probability P of success. The number of extra trials you must perform in order to observe a given number R of successes has a negative binomial distribution. However, consistent with a more general interpretation of the negative binomial, nbinrnd allows R to be any positive value, including nonintegers.

Example

Suppose you want to simulate a process that has a defect probability of 0.01. How many units might Quality Assurance inspect before finding three defective items?

r = nbinrnd(3,0.01,1,6) + 3
r =
   496   142   420   396   851   178

See Also
nbincdf, nbinfit, nbininv, nbinpdf, nbinstat

nbinpdf nbinstat