  In a previous paper, we described a new variant on the classical dN/dz test
which could be performed using upcoming redshift surveys. By observing the
velocity function of galaxies rather than their luminosity function, it is
possible to avoid many of the uncertainties of galaxy evolution while employing
a directly measurable quantity. We previously assumed that counting statistics
would dominate the errors in this method. Here, we present the results of
including cosmic variance and determine the impact of systematic effects on
application of this test to the upcoming DEEP2 Redshift Survey. For DEEP2,
cosmic variance should yield errors roughly twice those predicted from Poisson
statistics. Through Monte Carlo simulations we find that if the functional
form, but not the strength, of any of the major systematic effects (baryonic
infall, velocity errors, and incompleteness) is known, the systematic may
successfully be corrected for using the observed velocity function, leaving a
much smaller residual error. The total uncertainty from systematics is
comparable to that from cosmic variance, but correlated amongst redshift bins.
We find that DEEP2 can provide a much more precise measurement of the cosmic
equation of state parameter w than any available today, albeit weaker than some
other proposed tests.
