      j = 1
</pre>
<p>siendo <em>X_j</em> la <em>j</em>-ésima fila de la matriz muestral.
</p>
<p>Ejemplo:
</p>
<pre class="example">(%i1) load (descriptive)$
(%i2) s2 : read_matrix (file_search (&quot;wind.data&quot;))$
(%i3) fpprintprec : 7$ /* change precision for pretty output */
      [ 17.39587  13.75567  14.51734  19.59216  15.5774  ]
      [                                                  ]
      [ 13.75567  15.13913  13.43887  15.31145  15.12232 ]
      [                                          