  Recent observations by the Hubble Space Telescope of Cepheids in the Virgo
cluster imply a Hubble Constant $H_0=80\pm17$\ km/sec/Mpc. We attempt to
clarify some issues of interpretation of these results for determining the
global cosmological parameters $\Omega$ and $\Lambda$. Using the formalism of
Bayesian model comparison, the data suggest a universe with a nonzero
cosmological constant $\Lambda>0$, but vanishing curvature: $\Omega+\Lambda=1$.
