What is meant by the front bias and rear bias of the break of an automobile?

If your back brakes were stronger than your fronts then you could end up with the back end fishtaling where the back end slips about as its locks up. The fronts must be stronger that the backs so that the car brakes properly, they achive this by putting smaller brakes on the back or by fitting drums in some small cars/vans. Or they can fit a valve to the back hydraulics to reduce the pressure.