  The masses of the charged fermion and the mixing angles among quarks are
observed to be strongly hierarchical, while analogous parameters in the
neutrino sector appear to be structure-less or anarchical. We develop a class
of unified models based on SU(5) symmetry that explains these differing
features probabilistically. With the aid of three input parameters that are
hierarchical, and with the assumption that all the Yukawa couplings are
uncorrelated random variables described by Gaussian distributions, we show by
Monte Carlo simulations that the observed features of the entire fermion
spectrum can be nicely reproduced. We extend our analysis to an SU(5)-based
flavor U(1) model making use of the Froggatt-Nielsen mechanism where the order
one Yukawa couplings are modeled as random variables, which also shows good
agreement with observations.
