  We have previously shown that the linewidth distribution in AGN can be
accounted for by an axisymmetric broad emission line region. In this paper we
show that the linewidth distribution changes with redshift and that these
changes are dependent on H_0 and q_0. We show that relatively small samples of
AGN at high redshift with measured linewidth at half maximum can be used to
distinguish between values of H_0 and q_0. Furthermore larger low redshift
samples can be used to distinguish between luminosity functions and hence
different models of quasar evolution.
