  I present a new analysis of the MACHO Project 5.7 year Large Magellanic Cloud
(LMC) microlensing data set that incorporates the effects of contamination of
the microlensing event sample by variable stars. Photometric monitoring of
MACHO LMC microlensing event candidates by the EROS and OGLE groups has
revealed that one of these events is likely to be a variable star, while
additional data has confirmed that many of the other events are very likely to
be microlensing. This additional data on the nature of the MACHO microlensing
candidates is incorporated into a simple likelihood analysis to derive a
probability distribution for the number of MACHO microlens candidates that are
true microlensing events. This analysis shows that 10-12 of the 13 events that
passed the MACHO selection criteria are likely to be microlensing events, with
the other 1-3 being variable stars. This likelihood analysis is also used to
show that the main conclusions of the MACHO LMC analysis are unchanged by the
variable star contamination. The microlensing optical depth toward the LMC is =
1.0 +/- 0.3 * 10^{-7}. If this is due to microlensing by known stellar
populations, plus an additional population of lens objects in the Galactic
halo, then the new halo population would account for 16% of the mass of a
standard Galactic halo. The MACHO detection exceeds the expected background of
2 events expected from ordinary stars in standard models of the Milky Way and
LMC at the 99.98% confidence level. The background prediction is increased to 3
events if maximal disk models are assumed for both the MilkyWay and LMC, but
this model fails to account for the full signal seen by MACHO at the 99.8%
confidence level.
