  ====
                  i = 1
</pre>
<p>Exemplo:
</p>
<pre class="example">(%i1) load (descriptive)$
(%i2) load (numericalio)$
(%i3) s1 : read_list (file_search (&quot;pidigits.data&quot;))$
(%i4) central_moment (s1, 2), numer; /* a vari&acirc;ncia */
(%o4)                   8.425899999999999
(%i6) s2 : read_matrix (file_search (&quot;wind.data&quot;))$
(%i7) central_moment (s2, 3);
(%o7) [11.29584771375004, 16.97988248298583, 5.626661952750102, 
                             37.5986572057918, 25.8598190439