> <span class="op">)</span>    <span class="co"># expand theta to 2 dimensions</span></span>
<span><span class="co"># define design matrix</span></span>
<span><span class="va">theta.kDES</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://amices.org/mice/reference/cbind.html" class="external-link">cbind</a></span><span class="op">(</span> <span class="va">theta.k</span>, <span class="va">theta.k</span><span class="op">[</span>,<span class="fl">1</span><span class="op">]</span><span class=