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From pste...@apache.org
Subject cvs commit: jakarta-commons/math/xdocs/userguide index.xml stat.xml
Date Sun, 29 Feb 2004 21:25:09 GMT
psteitz     2004/02/29 13:25:09

  Modified:    math/xdocs/userguide index.xml stat.xml
  Log:
  Added more content to statistics and distributions user guide.
  
  Revision  Changes    Path
  1.7       +2 -2      jakarta-commons/math/xdocs/userguide/index.xml
  
  Index: index.xml
  ===================================================================
  RCS file: /home/cvs/jakarta-commons/math/xdocs/userguide/index.xml,v
  retrieving revision 1.6
  retrieving revision 1.7
  diff -u -r1.6 -r1.7
  --- index.xml	29 Feb 2004 18:50:10 -0000	1.6
  +++ index.xml	29 Feb 2004 21:25:08 -0000	1.7
  @@ -36,7 +36,7 @@
                 <li><a href="overview.html#dependencies">0.5 Dependencies</a></li>
               </ul></li>
   
  -           <li><a href="stat.html">1. Statistics</a>
  +           <li><a href="stat.html">1. Statistics and Distributions</a>
                   <ul>
                   <li><a href="stat.html#overview">1.1 Overview</a></li>
                   <li><a href="stat.html#univariate">1.2 Univariate statistics</a></li>
  
  
  
  1.9       +63 -6     jakarta-commons/math/xdocs/userguide/stat.xml
  
  Index: stat.xml
  ===================================================================
  RCS file: /home/cvs/jakarta-commons/math/xdocs/userguide/stat.xml,v
  retrieving revision 1.8
  retrieving revision 1.9
  diff -u -r1.8 -r1.9
  --- stat.xml	29 Feb 2004 18:50:10 -0000	1.8
  +++ stat.xml	29 Feb 2004 21:25:08 -0000	1.9
  @@ -23,14 +23,70 @@
       <title>The Commons Math User Guide - Statistics</title>
     </properties>
     <body>
  -    <section name="1 Statistics">
  +    <section name="1 Statistics and Distributions">
         <subsection name="1.1 Overview" href="overview">
  -        <p>This is yet to be written. Any contributions will be greatfully
  -          accepted!</p>
  +        <p>
  +          The statistics and distributions packages provide frameworks and implementations
for
  +          basic univariate statistics, frequency distributions, bivariate regression, 
t- and chi-square test 
  +          statistics and some commonly used probability distributions.
  +        </p>
         </subsection>
         <subsection name="1.2 Univariate statistics" href="univariate">
  -        <p>This is yet to be written. Any contributions will be gratefully
  -          accepted!</p>
  +        <p>
  +          The stat package includes a framework and default implementations for the following
univariate
  +          statistics:
  +          <ul>
  +            <li>arithmetic and geometric means</li>
  +            <li>variance and standard deviation</li>
  +            <li>sum, product, log sum, sum of squared values</li>
  +            <li>minimum, maximum, median, and percentiles</li>
  +            <li>skewness and kurtosis</li>
  +            <li>first, second, third and fourth moments</li>
  +          </ul>
  +        </p>
  +        <p>
  +          With the exception of percentiles and the median, all of these statistics can
be computed without
  +          maintaining the full list of input data values in memory.  The stat package provides
interfaces and
  +          implementations that do not require value storage as well as implementations
that operate on arrays
  +          of stored values.  
  +        </p>
  +        <p>
  +          The top level interface is 
  +          <a href="../apidocs/org/apache/commons/math/stat/univariate/UnivariateStatistic.html">
  +          org.apache.commons.math.stat.univariate.UnivariateStatistic.</a> This interface,
implemented by
  +          all statistics, consists of <code>evaluate()</code> methods that
take double[] arrays as arguments and return 
  +          the value of the statistic.   This interface is extended by 
  +          <a href="../apidocs/org/apache/commons/math/stat/univariate/StorelessUnivariateStatistic.html">
  +          org.apache.commons.math.stat.univariate.StorelessUnivariateStatistic,</a>
which adds <code>increment(),</code>
  +          <code>getResult()</code> and associated methods to support "storageless"
implementations that
  +          maintain counters, sums or other state information as values are added using
the <code>increment()</code>
  +          method.  
  +        </p>
  +        <p>
  +          Abstract implementations of the top level interfaces are provided in 
  +          <a href="../apidocs/org/apache/commons/math/stat/univariate/AbstractUnivariateStatistic.html">
  +          org.apache.commons.math.stat.univariate.AbstractUnivariateStatistic</a>
and
  +          <a href="../apidocs/org/apache/commons/math/stat/univariate/AbstractStorelessUnivariateStatistic.html">
  +          org.apache.commons.math.stat.univariate.AbstractStorelessUnivariateStatistic</a>
respectively.
  +        </p>
  +        <p>
  +          Each statistic is implemented as a separate class, in one of the subpackages
(moment, rank, summary) and
  +          each extends one of the abstract classes above (depending on whether or not value
storage is required to 
  +          compute the statistic).
  +          There are several ways to instantiate and use statistics.  Statistics can be
instantiated and used directly,  but it is
  +          generally more convenient to access them using the provided aggregates: 
  +          <table>
  +            <tr><th>Aggregate</th><th>Statistics Included</th><th>Values
stored?</th></tr>
  +            <tr><td><a href="../apidocs/org/apache/commons/math/stat/DescriptiveStatistics.html">
  +            org.apache.commons.math.stat.DescriptiveStatistics</a></td><td>All</td><td>Yes</td></tr>
  +            <tr><td><a href="../apidocs/org/apache/commons/math/stat/SummaryStatistics.html">
  +            org.apache.commons.math.stat.SummaryStatistics</a></td><td>min,
max, mean, geometric mean, n, sum, sum of squares, standard deviation, variance</td><td>No</td></tr>
  +          </table>
  +          TODO: add code sample
  +          There is also a utility class, <a href="../apidocs/org/apache/commons/math/stat/StatUtils.html">
  +           org.apache.commons.math.stat.StatUtils,</a> that provides static methods
for computing statistics
  +           from double[] arrays. 
  +        </p>
         </subsection>
         <subsection name="1.3 Frequency distributions" href="frequency">
           <p>This is yet to be written. Any contributions will be gratefully
  @@ -73,6 +129,7 @@
               <tr><td>F</td><td>createFDistribution</td><td><div>Numerator
degrees of freedom</div><div>Denominator degrees of freedom</div></td></tr>
               <tr><td>Gamma</td><td>createGammaDistribution</td><td><div>Alpha</div><div>Beta</div></td></tr>
               <tr><td>Hypergeometric</td><td>createHypogeometricDistribution</td><td><div>Population
size</div><div>Number of successes in population</div><div>Sample
size</div></td></tr>
  +            <tr><td>Normal (Gaussian)</td><td>createNormalDistribution</td><td><div>Mean</div><div>Standard
Deviation</div></td></tr>
               <tr><td>t</td><td>createTDistribution</td><td><div>Degrees
of freedom</div></td></tr>
             </table>
           </p>
  
  
  

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