Cold plus hot (neutrino) dark matter models are studied and compared w
ith the tilted cold dark matter models (which have a non-Zel'dovich in
itial density perturbation spectrum). For the hybrid dark matter model
s, a simpler treatment for the relativistic neutrinos is presented. Th
e numerical results of this treatment are shown to be in good agreemen
t with those given by other authors. Comparing the theoretical and the
observational results of the quadrupole fluctuations of the cosmic ba
ckground radiation and the large-scale velocity field of galaxies, the
hybrid dark matter models require a fraction of neutrino density OMEG
A(nu) congruent-to 0.3, a fraction of cold dark matter OMEGA(c) congru
ent-to 0.7 and a number of massive neutrino species N(nu) = 1 for the
case of Hubble's constant H-0 = 50 km s-1 Mpc-1. The distribution of c
omoving number density of quasars at high redshifts is studied using t
he Press-Schechter theory. The calculations show that the hybrid dark
matter model (OMEGA(c) congruent-to 0.7, OMEGA(nu) congruent-to 0.3) a
nd the tilted CDM model with n = 0.7 approximately 0.8 both account fo
r the observed quasar abundance at high redshift.