∞</code> if <code>α &lt;= 1</code>,</li>
 <li><code>α * k / (α - 1)</code> otherwise.</li>
 </ul></div>
<dl><dt><span class="strong">Returns:</span></dt><dd>the mean or <code>Double.NaN</code> if it is not defined</dd></dl>
</li>
</ul>
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<h4>getNumericalVariance</h4>
<pre>public&nbsp;double&nbsp;getNumericalVariance()</pre>
<div class="block">Use this method to get the numerical value of the variance of this
 