n class="op">]</span> <span class="op">&lt;-</span> <span class="op">-</span><span class="fl">0.5</span></span>
<span><span class="co"># estimate model</span></span>
<span><span class="va">res2</span> <span class="op">&lt;-</span> <span class="fu">mirt</span><span class="fu">::</span><span class="fu"><a href="https://rdrr.io/pkg/mirt/man/mirt.html" class="external-link">mirt</a></span><span class="op">(</span> <span class="va">dat</span><span class="op">[</span>,<span class="fl">1</span><span class="op">:</