  Recently, Guidorzi et al. (2005) expanded the size of the sample of GRBs for
which variabilities and peak luminosities have been measured, from 11 to 32.
They confirm the existence of a correlation, but find a dramatically different
relationship between L and V than had originally been found. We find that this
is the result of improper statistical methodology. When we fit a model to the
data that accommodates both statistical variance (in two dimensions) and sample
variance, we find that L ~ V^3.4(+0.9,-0.6) with a sample variance of
sigma_logV = 0.20(+0.04,-0.04), which is consistent with the original finding
of Reichart et al. (2001) -- L ~ V^3.3(+1.1,-0.9) with a sample variance of
sigma_logV = 0.18(+0.07,-0.05) -- and inconsistent with the finding of Guidorzi
et al. (2005): L ~ V^1.3(+0.8,-0.4) with sample variance assumed to be zero.
