  We find that the empirical relation between the longitudinal and Hall
resistivities (i.e. Rxx and Rxy) and its counterpart between the Seebeck and
Nernst coefficients (i.e. Sxx and Sxy), both originally discovered in
two-dimensional electron gases, hold remarkably well for graphene in the
quantum transport regime except near the Dirac point. The validity of the
relations is cross-examined by independently varying the magnetic field and the
carrier density in graphene. We demonstrate that the pre-factor, \alpha_s, does
not depend on carrier density in graphene. By tuning the carrier mobility
therefore the degree of disorders, we find that the pre-factor stays unchanged.
Near the Dirac point, different mechanisms at low densities such as carrier
localization may be responsible for the breakdown of these relations.
