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<div class="refentry" title="Struct template skewness_impl">
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<h2><span class="refentrytitle">Struct template skewness_impl</span></h2>
<p>boost::accumulators::impl::skewness_impl — Skewness estimation. </p>
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<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="emphasis"><em>// In header: <<a class="link" href="../../../accumulators/reference.html#header.boost.accumulators.statistics.skewness_hpp" title="Header <boost/accumulators/statistics/skewness.hpp>">boost/accumulators/statistics/skewness.hpp</a>>
</em></span><span class="bold"><strong>template</strong></span><<span class="bold"><strong>typename</strong></span> Sample>
<span class="bold"><strong>struct</strong></span> <a class="link" href="skewness_impl.html" title="Struct template skewness_impl">skewness_impl</a> {
<span class="emphasis"><em>// types</em></span>
<span class="bold"><strong>typedef</strong></span> numeric::functional::average< Sample, Sample >::result_type <a name="boost.accumulators.impl.skewness_impl.result_type"></a>result_type;
<span class="emphasis"><em>// <a class="link" href="skewness_impl.html#boost.accumulators.impl.skewness_implconstruct-copy-destruct">construct/copy/destruct</a></em></span>
<a class="link" href="skewness_impl.html#id558096-bb">skewness_impl</a>(dont_care);
<span class="emphasis"><em>// <a class="link" href="skewness_impl.html#id558073-bb">public member functions</a></em></span>
<span class="bold"><strong>template</strong></span><<span class="bold"><strong>typename</strong></span> Args> <span class="type">result_type</span> <a class="link" href="skewness_impl.html#id558076-bb">result</a>(Args <span class="bold"><strong>const</strong></span> &) <span class="bold"><strong>const</strong></span>;
};</pre></div>
<div class="refsect1" title="Description">
<a name="id673712"></a><h2>Description</h2>
<p>The skewness of a sample distribution is defined as the ratio of the 3rd central moment and the <span class="inlinemediaobject"><img src="../../../images/accumulators/form_52.png"></span>-th power of the 2nd central moment (the variance) of the sampless 3. The skewness can also be expressed by the simple moments:</p>
<div class="equation">
<a name="id673742"></a><p class="title"><b>Equation 1.11. </b></p>
<div class="equation-contents"><div class="mediaobject" align="center"><img src="../../../images/accumulators/form_53.png" align="middle"></div></div>
</div>
<p><br class="equation-break"></p>
<p>where <span class="inlinemediaobject"><img src="../../../images/accumulators/form_14.png"></span> are the <span class="inlinemediaobject"><img src="../../../images/accumulators/form_15.png"></span>-th moment and <span class="inlinemediaobject"><img src="../../../images/accumulators/form_16.png"></span> the mean (first moment) of the <span class="inlinemediaobject"><img src="../../../images/accumulators/form_17.png"></span> samples. </p>
<div class="refsect2" title="skewness_impl public construct/copy/destruct">
<a name="id673851"></a><h3>
<a name="boost.accumulators.impl.skewness_implconstruct-copy-destruct"></a><code class="computeroutput">skewness_impl</code>
public
construct/copy/destruct</h3>
<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><pre class="literallayout"><a name="id558096-bb"></a>skewness_impl(dont_care);</pre></li></ol></div>
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<div class="refsect2" title="skewness_impl public member functions">
<a name="id673885"></a><h3>
<a name="id558073-bb"></a><code class="computeroutput">skewness_impl</code> public member functions</h3>
<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><pre class="literallayout"><span class="bold"><strong>template</strong></span><<span class="bold"><strong>typename</strong></span> Args> <span class="type">result_type</span> <a name="id558076-bb"></a>result(Args <span class="bold"><strong>const</strong></span> & args) <span class="bold"><strong>const</strong></span>;</pre></li></ol></div>
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<td align="right"><div class="copyright-footer">Copyright © 2005, 2006 Eric Niebler<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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