<span class="va">Qmatrix</span><span class="op">)</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"F1"</span>, <span class="st">"F1sq"</span> <span class="op">)</span></span>
<span><span class="co"># estimate model</span></span>
<span><span class="va">mod9</span> <span class="op">&lt;-</span> <span class="fu">sirt</span><span class="fu">::</span><span class="fu">smirt</span><span class="