  Flavor symmetry ($T^{'} \times Z_2$) where $T^{'}$ is the binary tetrahedral
group predicts for neutrino mixing angles $\theta_{13} = \sqrt{2}
(\frac{\pi}{4} - \theta_{23})$ and, with one phenomenological input, provides
upper and lower bounds on both $\theta_{13}$ and $\theta_{23}$. The predictions
arise from the deviation of the Cabibbo angle $\Theta_{12}$ from its
lowest-order value $\tan 2\Theta_{12} = (\sqrt{2})/3$ and from the $T^{'}$
mechanism which relates mixing of $(\nu_{\tau}, \nu_{\mu}, \nu_e)$ neutrinos to
mixing of $(s, d)$ quarks.
