org/packages/base/topics/factor">factor</a></span>(aids<span class="op">$</span>obstime)</a>
<a class="sourceLine" id="cb4-3" title="3"></a>
<a class="sourceLine" id="cb4-4" title="4">fm1 &lt;-<span class="st"> </span><span class="kw">geeglm</span>(CD4count <span class="op">~</span><span class="st"> </span>obstimef, <span class="dt">family =</span> <span class="kw"><a href="https://www.rdocumentation.org/packages/stats/topics/family">poisson</a></span>(), <span class="dt">data =</span> aids, </a>
<a class="