  Scattering among electrons generates a distinct contribution to electrical
resistivity that follows a quadratic temperature dependence. In
strongly-correlated electron systems, the prefactor A of this T$^2$ resistivity
scales with the magnitude of the electronic specific heat. Here, we show that
one can change the magnitude of A by four orders of magnitude in metallic
SrTiO3 by tuning the concentration of the carriers and consequently, the Fermi
energy. The T$^2$ behavior persists in the single-band dilute limit despite the
absence of two known mechanisms for T$^2$ behavior, distinct electron
reservoirs and Umklapp processes. The results highlight the absence of a
microscopic theory for momentum decay through electron-electron scattering in
different Fermi liquids.
