 of these parameters from their posterior
distribution.</p>
<p>The modeled parameter <code>tau_y</code> is transformed from a precision to
a scale parameter and assigned to the variable <code>sigma_y</code> in the
<code>transformed parameters</code> block. Thus the variable <code>sigma_y</code>
is considered a derived quantity — its value is entirely determined
by the values of other variables.</p>
<p>The <code>generated quantities</code> block defines a value
<code>variance_y</code>, which is defined as 