external-link">log</a></span><span class="op">(</span><span class="va">serBilir</span><span class="op">)</span> <span class="op">~</span> <span class="fu"><a href="https://rdrr.io/r/stats/poly.html" class="external-link">poly</a></span><span class="op">(</span><span class="va">year</span>, <span class="fl">2</span><span class="op">)</span> <span class="op">*</span> <span class="va">sex</span>, data <span class="op">=</span> <span class="va">pbc2</span>, </span>
<span>          random <span class="op">=</spa