pan class="r-in"><span class="fu"><a href="https://rdrr.io/r/graphics/plot.default.html" class="external-link">plot</a></span><span class="op">(</span><span class="va">subgrp.model</span>, type <span class="op">=</span> <span class="st">"interaction"</span><span class="op">)</span></span>
<span class="r-plt img"><img src="plot-3.png" alt="" width="700" height="433"></span>
<span class="r-in"></span>
<span class="r-in"><span class="fu"><a href="https://rdrr.io/r/graphics/plot.default.html" class="external-li