an> <span class="op">&gt;</span> <span class="fu"><a href="https://rdrr.io/r/base/levels.html" class="external-link">levels</a></span><span class="op">(</span><span class="va">gen</span><span class="op">)</span><span class="op">[</span><span class="fl">1</span><span class="op">]</span> <span class="op">~</span> <span class="va">hgt</span> <span class="op">+</span> <span class="va">hc</span>, family <span class="op">=</span> <span class="va">binomial</span><span class="op">)</span><span class="op">)</span></