stdev - standard deviation of the values of a vector or matrix

### Calling Sequence

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

### Parameters

- `x` : real or complex vector or matrix

### Description

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

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

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

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

### Examples

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

### Author

Carlos Klimann

### Bibliography

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