o">#&gt; 3 -2.979219  -1.917001         NA           NA        NA          NA</span></span>
<span><span class="co">#&gt; 4 -5.680918  -2.603167         NA           NA        NA          NA</span></span></code></pre></div>
<p>This result is fairly similar, although there is stronger evidence
now that the slopes are not the same, perhaps because the slope for
group 1 is now noticeably steeper.</p>
<div class="sourceCode" id="cb12"><pre class="downlit sourceCode r">
<code class="sourceCode R"><span><span clas