dinates <code>z</code>, <span class="math inline">\(\rho\)</span>
(horizontal distance, <code>rho</code>) and <code>r</code> (euclidean
distance), the following statistics are calculated:</p>
<ul>
<li>arithmetic (<code>mean.arit.z/rho/r</code>), quadratic
(<code>mean.qua.z/rho/r</code>), geometric
(<code>mean.geom.z/rho/r</code>) and harmonic means
(<code>mean.harm.z/rho/r</code>)</li>
<li>median (<code>median.z/rho/r</code>)</li>
<li>mode (<code>mode.z/rho/r</code>)</li>
<li>variance (<code>var.z/rho/r</co