betastat

Beta mean and variance

Syntax

```[M,V] = betastat(A,B) ```

Description

`[M,V] = betastat(A,B)`, with `A>0` and `B>0`, returns the mean of and variance for the beta distribution with parameters specified by `A` and `B`. `A` and `B` can be vectors, matrices, or multidimensional arrays that have the same size, which is also the size of `M` and `V`. A scalar input for `A` or `B` is expanded to a constant array with the same dimensions as the other input.

The mean of the beta distribution with parameters a and b is $a/\left(a+b\right)$ and the variance is

`$\frac{ab}{\left(a+b+1\right){\left(a+b\right)}^{2}}$`

Examples

If parameters a and b are equal, the mean is 1/2.

```a = 1:6; [m,v] = betastat(a,a) m = 0.5000 0.5000 0.5000 0.5000 0.5000 0.5000 v = 0.0833 0.0500 0.0357 0.0278 0.0227 0.0192```

Version History

Introduced before R2006a