[doc] misc. fix & improvements
[scilab.git] / scilab / modules / statistics / help / en_US / 3_dispersion_widths / stdevf.xml
1 <?xml version="1.0" encoding="UTF-8"?>
2 <!--
3  * Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
4  * Copyright (C) 2000 - INRIA - Carlos Klimann
5  *
6  * Copyright (C) 2012 - 2016 - Scilab Enterprises
7  *
8  * This file is hereby licensed under the terms of the GNU GPL v2.0,
9  * pursuant to article 5.3.4 of the CeCILL v.2.1.
10  * This file was originally licensed under the terms of the CeCILL v2.1,
11  * and continues to be available under such terms.
12  * For more information, see the COPYING file which you should have received
13  * along with this program.
14  *
15  -->
16 <refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:svg="http://www.w3.org/2000/svg" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook" xmlns:scilab="http://www.scilab.org" xml:lang="en" xml:id="stdevf">
17     <refnamediv>
18         <refname>stdevf</refname>
19         <refpurpose>standard deviation</refpurpose>
20     </refnamediv>
21     <refsynopsisdiv>
22         <title>Syntax</title>
23         <synopsis>s=stdevf(x,fre)
24             s=stdevf(x,fre,'r') or s=stdevf(x,fre,1)
25             s=stdevf(x,fre,'c') or s=stdevf(x,fre,2)
26         </synopsis>
27     </refsynopsisdiv>
28     <refsection>
29         <title>Arguments</title>
30         <variablelist>
31             <varlistentry>
32                 <term>x</term>
33                 <listitem>
34                     <para>real or complex vector or matrix</para>
35                 </listitem>
36             </varlistentry>
37             <varlistentry>
38                 <term>fre</term>
39                 <listitem>
40                     <para>real or complex vector or matrix</para>
41                 </listitem>
42             </varlistentry>
43         </variablelist>
44     </refsection>
45     <refsection>
46         <title>Description</title>
47         <para>
48             This function   computes the standard  deviation  of the
49             values  of a vector  or matrix <literal>   x</literal>, each of them
50             counted with  a  frequency  given  by the  corresponding
51             values of the  integer vector or matrix  <literal> fre</literal> who
52             has the same type of <literal> x</literal>.
53         </para>
54         <para>
55             For  a vector or matrix  <literal>  x</literal>, s=stdevf(x,fre) (or
56             <literal> s=stdevf(x,fre,'*') </literal>  returns in scalar <literal> s</literal>
57             the standard deviation of all the entries  of <literal> x</literal>,
58             each value  counted  with the multiplicity  indicated by
59             the corresponding value of <literal> fre</literal>.
60         </para>
61         <para>
62             <literal>s=stdevf(x,fre,'r')</literal>   (or,     equivalently,
63             <literal>s=stdevf(x,fre,1)</literal>) returns in each  entry of  the row
64             vector  <literal> s</literal>  of type  1xsize(x,'c')  the standard
65             deviation of each column of <literal> x</literal>, each value counted
66             with  the multiplicity  indicated  by the  corresponding
67             value of <literal> fre</literal>.
68         </para>
69         <para>
70             <literal>s=stdevf(x,fre,'c')</literal>    (or,   equivalently,
71             <literal> s=stdevf(x,fre,2)</literal>)  returns   in each  entry  of  the
72             column vector  <literal>  s</literal>   of type  size(x,'c')x1   the
73             standard  deviation of each row  of <literal> x</literal>, each value
74             counted    with the  multiplicity    indicated   by  the
75             corresponding value of <literal> fre</literal>.
76         </para>
77     </refsection>
78     <refsection>
79         <title>Examples</title>
80         <programlisting role="example"><![CDATA[
81 x=[0.2113249 0.0002211 0.6653811;0.7560439 0.9546254 0.6283918]
82 fre=[1 2 3;3 4 3]
83 m=stdevf(x,fre)
84 m=stdevf(x,fre,'r')
85 m=stdevf(x,fre,'c')
86  ]]></programlisting>
87     </refsection>
88     <refsection>
89         <title>Bibliography</title>
90         <para>
91             Wonacott, T.H. &amp; Wonacott, R.J.; Introductory Statistics, fifth edition, J.Wiley &amp; Sons, 1990.
92         </para>
93     </refsection>
94 </refentry>