  A well-known feature in transport data of the topological Kondo insulator
SmB$_6$ is the sign change in the Hall coefficient at 65 K. Carriers in SmB$_6$
are known to be negative, but above 65 K, the Hall sign suggests that the
carriers are positive. Here, we extend Hall measurements up to 400 K and
observe that the Hall coefficient changes back to the correct (negative) sign
at about 305 K. We interpret the anomalous sign of the Hall coefficient in the
context of skew scattering arising from the strong correlations between the $f$
and $d$ electrons. At energy scales where the gap is closed, the number of $d$
electrons in resonance with the $f$ electrons at the Fermi energy varies. When
a large proportion of $d$ and $f$ electrons are in resonance, skew scattering
is dominant, leading to the observation of the positive sign, but when fewer
are in resonance, conventional scattering mechanisms dominate instead.
