</span> <span class="comment">// location.</span>
   <span class="identifier">RealType</span> <span class="identifier">standard_deviation</span><span class="special">()</span><span class="keyword">const</span><span class="special">;</span> <span class="comment">// scale.</span>
   <span class="comment">// Synonyms, provided to allow generic use of find_location and find_scale.</span>
   <span class="identifier">RealType</span> <span class="identifier">location</span><span class="special">()</span><span clas