Last update : July 2000

variance - variance of the values of a vector or matrix

### Calling Sequence

  `s=variance(x)`
  `s=variance(x,'r') or m=variance(x,1)`
  `s=variance(x,'c') or m=variance(x,2)`

### Parameters

- `x`: real or complex vector or matrix

### Description

This function computes the variance of the values of a vector or matrix `x`.

For a vector or a matrix `x`, `s=variance(x)` returns in the scalar `s` the variance of all the entries of `x`.

`s=variance(x,'r')` (or, equivalently, `s=variance(x,1)`) is the rowwise variance. It returns in each entry of the row vector s the variance of each column of `x`.

`s=variance(x,'c')` (or, equivalently, `s=variance(x,2)`) is the columnwise standard deviation. It returns in each entry of the column vector `s` the variance of each row of `x`.

### Examples

    x=[0.2113249 0.0002211 0.6653811;0.7560439 0.4453586 0.6283918]
    s=variance(x)
    s=variance(x,'r')
    s=variance(x,'c')

### Author

Carlos Klimann

### Bibliography

Wonacott, T.H. & Wonacott, R.J.; Introductory Statistics, fifth edition, J.Wiley & Sons, 1990.