## RANDBETA Beta Deviate Random Number Generator

Section: Random Number Generation

### Usage

Creates an array of beta random deviates based on the supplied two parameters. The general syntax for `randbeta` is

       y = randbeta(alpha, beta)

where `alpha` and `beta` are the two parameters of the random deviate. There are three forms for calling `randbeta`. The first uses two vectors `alpha` and `beta` of the same size, in which case the output `y` is the same size as both inputs, and each deviate uses the corresponding values of `alpha` and `beta` from the arguments. In the other forms, either `alpha` or `beta` are scalars.

### Function Internals

The probability density function (PDF) of a beta random variable is

for `x` between 0 and 1. The function `B(a,b)` is defined so that the integral of `f(x)` is 1.

### Example

Here is a plot of the PDF of a beta random variable with `a=3`, `b=7`.

    --> a = 3; b = 7;
    --> x = (0:100)/100; t = x.^(a-1).*(1-x).^(b-1);
    --> t = t/(sum(t)*.01);
    --> plot(x,t);
    -->
    quit

which is plotted as

If we generate a few random deviates with these values, we see they are distributed around the peak of roughly `0.25`.

    --> randbeta(3*ones(1,5),7*ones(1,5))

    ans =

        0.2777    0.0642    0.3305    0.5259    0.4003

    -->
    quit