and</p>
<div class="equation">
<a name="id780026"></a><p class="title"><b>Equation&#160;2.&#160;</b></p>
<div class="equation-contents"><div class="mediaobject" align="center"><img src="../../../images/accumulators/form_6.png" align="middle"></div></div>
</div>
<p><br class="equation-break"></p>
<p><span class="inlinemediaobject"><img src="../../../images/accumulators/form_7.png"></span> being the number of samples and <span class="inlinemediaobject"><img src="../../../images/accumulators/form_8.png"></span