ivatives">root-finding
            without derivatives</a>.
          </p>
<p>
            But in this normal distribution case, we could be even smarter and make
            a direct calculation.
          </p>
<pre class="programlisting"><span class="identifier">normal</span> <span class="identifier">s</span><span class="special">;</span> <span class="comment">// For standard normal distribution,</span>
<span class="keyword">double</span> <span class="identifier">sd</span> <span class="special">=</span> <