  Analytic expressions for distance-redshift relations which have been
corrected for the effects of some inhomogeneities in the
Friedmann-Robertson-Walker (FRW) mass density are used to illustrate the
significance of inhomogeneities on a determination of $q_0$ made by using Type
Ia supernovae. The value of $q_0$ inferred from a given set of observations
depends on the fractional amount of matter in inhomogeneities and is up to 50
percent larger than that obtained by using the standard Mattig $m$-$z$ result
for pure dust FRW models.
