  We refine our recent analysis of the electroweak precision data at the \PZO\
pole by including the hadronic decay modes of the \PZO. Within the framework of
an effective Lagrangian we parametrize $SU(2)$ violation by the additional
process-specific parameters $\De y_\nu$, $\De\yh$, and $\De\yb$ (for the
$\PZO\nu\bar\nu$, $\PZO\Pq\bar\Pq$, and $\PZO\Pb\bar\Pb$ vertices) together
with the previously introduced parameters $\De x$, $\De y$, and $\eps$. We find
that a six-parameter analysis of the experimental data is indeed feasible, and
it is carried out in addition to a four-parameter fit for $\De x$, $\De y$,
$\eps$, and $\De\yb$ only. We reemphasize that the experimental data have
become sensitive to the (combined) magnitude of the vertex corrections at the
$\PWp\Pl\bar\nu$ ($\PWm\nu\bar\Pl$) and $\PZO\Pl\bar\Pl$ vertices, $\De y$,
which is insensitive to the notion of the Higgs mechanism but dependent on the
non-Abelian, trilinear vector-boson coupling. Full explicit analytical results
for the standard one-loop predictions for the above-mentioned parameters are
given, and the leading two-loop top-quark effects are included. The analytic
formluae for the analysis of the experimental data in terms of the parameters
$\De x$, $\De y$ etc.\ are presented in order to encourage experimentalists to
persue such an analysis by themselves with future data.
