len<span class="op">=</span><span class="fl">15</span> <span class="op">)</span></span>
<span><span class="va">theta.k</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/r/base/matrix.html" class="external-link">as.matrix</a></span><span class="op">(</span> <span class="va">theta.k</span>, ncol<span class="op">=</span><span class="fl">1</span> <span class="op">)</span></span>
<span><span class="co"># define design matrix</span></span>
<span><span class="va">theta.kDES</span> <spa