slippage you might say my will turn this much but what if it slipped and you don't know what your next state is going to be if you don't know how much it slipped and it could be unmad unmodeled variations in the floor that effect essentially where you end up all right so those are two examples just to motivate why we might want to deal with probability distributions in that yeah if this is what we're faced with or the helicopters what we're faced with we're now going to have a deterministic notion of this is the state we're just