"co"># Cov[1,2]=Cov[1,3]=Cov[1,4]=Cov[2,3]=Cov[2,4]=Cov[3,4]=0</span></span>
<span></span>
<span><span class="co"># estimate model</span></span>
<span><span class="va">mod4</span> <span class="op">&lt;-</span> <span class="fu">sirt</span><span class="fu">::</span><span class="fu">smirt</span><span class="op">(</span> <span class="va">dat</span>, Qmatrix<span class="op">=</span><span class="va">Qmatrix1</span>, irtmodel<span class="op">=</span><span class="st">"comp"</span>, est.a<span class="op">=</span><sp