 id="cb6-4"><a href="#cb6-4" aria-hidden="true" tabindex="-1"></a>  <span class="dt">real</span>&lt;<span class="kw">lower</span>=<span class="dv">0</span>&gt; sigma;</span>
<span id="cb6-5"><a href="#cb6-5" aria-hidden="true" tabindex="-1"></a>}</span>
<span id="cb6-6"><a href="#cb6-6" aria-hidden="true" tabindex="-1"></a><span class="kw">model</span> {</span>
<span id="cb6-7"><a href="#cb6-7" aria-hidden="true" tabindex="-1"></a>  y_train ~ normal(alpha + beta * x_train, sigma);</span>
<span id="cb6-8"><a