e number of columns will be the
number of factor levels, otherwise it will be the number of
factor levels used in <code>groups</code>.</p></li>
<li><p>When <code>returnType="input"</code> the output is a numeric matrix
with the same dimensions as the input data. This output is
intended for use with <code>rmOutliers=TRUE</code> which will replace
outlier points with <code>NA</code> values. Therefore, this matrix can
be used to see the location of outliers.</p></li>
</ul><p>The function also returns attribute