  We investigate dipole modes in a trapped Bose--Fermi mixture gas in the
normal phase, composed of single-species bosons and single-species fermions
with $s$-wave scattering. In the extremely low temperature regime,
Bose--Einstein statistics and Fermi--Dirac statistics may give rise to an
interesting temperature dependence of collective modes. Applying the moment
method to the linearized Boltzmann equation, we study the transition of the
dipole modes between the hydrodynamic regime and the collisionless regime.
