 title="4">              <span class="dt">corstr =</span> <span class="st">"exchangeable"</span>)</a>
<a class="sourceLine" id="cb1-5" title="5"></a>
<a class="sourceLine" id="cb1-6" title="6">gm2 &lt;-<span class="st"> </span><span class="kw">geeglm</span>(serCholD <span class="op">~</span><span class="st"> </span><span class="kw">ns</span>(year, <span class="dt">knots =</span> <span class="kw"><a href="https://www.rdocumentation.org/packages/base/topics/c">c</a></span>(<span class="dv">2</span>, <span cla