stdevf
======

standard deviation



Calling Sequence
~~~~~~~~~~~~~~~~


::

    s=stdevf(x,fre)
    s=stdevf(x,fre,'r') or s=stdevf(x,fre,1)
    s=stdevf(x,fre,'c') or s=stdevf(x,fre,2)




Arguments
~~~~~~~~~

:x real or complex vector or matrix
: :fre real or complex vector or matrix
:



Description
~~~~~~~~~~~

This function computes the standard deviation of the values of a
vector or matrix `x`, each of them counted with a frequency given by
the corresponding values of the integer vector or matrix `fre` who has
the same type of `x`.

For a vector or matrix `x`, s=stdevf(x,fre) (or `s=stdevf(x,fre,'*')`
returns in scalar `s` the standard deviation of all the entries of
`x`, each value counted with the multiplicity indicated by the
corresponding value of `fre`.

`s=stdevf(x,fre,'r')` (or, equivalently, `s=stdevf(x,fre,1)`) returns
in each entry of the row vector `s` of type 1xsize(x,'c') the standard
deviation of each column of `x`, each value counted with the
multiplicity indicated by the corresponding value of `fre`.

`s=stdevf(x,fre,'c')` (or, equivalently, `s=stdevf(x,fre,2)`) returns
in each entry of the column vector `s` of type size(x,'c')x1 the
standard deviation of each row of `x`, each value counted with the
multiplicity indicated by the corresponding value of `fre`.



Examples
~~~~~~~~


::

    x=[0.2113249 0.0002211 0.6653811;0.7560439 0.9546254 0.6283918]
    fre=[1 2 3;3 4 3]
    m=stdevf(x,fre)
    m=stdevf(x,fre,'r')
    m=stdevf(x,fre,'c')




Bibliography
~~~~~~~~~~~~

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