p'>(</span><span class='va'>ed50</span> <span class='op'>+</span> <span class='va'>dose</span><span class='op'>)</span><span class='op'>)</span> <span class='op'>+</span>
  <span class='fu'><a href='obs_proportional.html'>obs_proportional</a></span><span class='op'>(</span><span class='op'>~</span><span class='va'>effect</span>, var_prop <span class='op'>=</span> <span class='fl'>1</span><span class='op'>)</span>

<span class='co'># add estimation task using importance sampling, covariance step</span>
<span