tion matrix is assumed to be the exchangeable one. We solve the two GEEs using the following calls to <code>geeglm()</code> from package <strong>geepack</strong>:</p>
<div class="sourceCode" id="cb1"><pre class="sourceCode r"><code class="sourceCode r"><a class="sourceLine" id="cb1-1" title="1">pbc2<span class="op">$</span>serCholD &lt;-<span class="st"> </span><span class="kw"><a href="https://www.rdocumentation.org/packages/base/topics/numeric">as.numeric</a></span>(pbc2<span class="op">$</span>serChol <s