s="va">mres</span><span class="op">)</span>   <span class="co"># item information</span></span>
<span><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">mres</span>,type<span class="op">=</span><span class="st">"trace"</span><span class="op">)</span>  <span class="co"># item category functions</span></span>
<span></span>
<span><span class="co"># graded response model with equal slopes</span></span>
<span><spa