  We use a model previously formulated based on the double exchange mechanism
and diagonal disorder to calculate magnetization and conductivity for
La_{1-x}Sr_xMnO_3 type crystals as a function of temperature. The model
represents each Mn^{4+} ion by a spin S=1/2, on which an electron can be added
to produce Mn$^{3+}$. We include a hopping energy $t,$ two strong intratomic
interactions: exchange $J$, and Coulomb $U,$ and, to represent in a simple way
the effects of disorder, a Lorentzian distribution of diagonal energies of
width $\Gamma $ at the Mn sites.
  In the strong coupling limit, $J,U>>t,\Gamma $, the model results can be
expressed in terms of $t$ and $\Gamma .$
  We use the results of the model to draw ''phase diagrams'' that separate
ferromagnetic from paramagnetic states and also ''insulating '' states where
the Fermi level falls in a region of localized states from ''metallic '' where
the Fermi level falls in a region of extended states.
  Finally, assuming that particles in extended states make the largest
contribution to conductivity, we calculate the resistivity for different
concentrations and magnetic fields and compare with experiment.
  We conclude that for the model can be used successfully to represent the
transport properties of the systems under consideration.
