 class="op">(</span><span class="fu"><a href="https://rdrr.io/r/stats/lm.html" class="external-link">lm</a></span><span class="op">(</span><span class="va">X</span><span class="op">[</span>,<span class="fl">4</span><span class="op">]</span> <span class="op">~</span> <span class="va">X</span><span class="op">[</span>,<span class="fl">1</span><span class="op">:</span><span class="fl">3</span><span class="op">]</span><span class="op">)</span>, type<span class="op">=</span><span class="st">"response"</span><spa