i need help to get the risidual for these data points (21.9, 3.69) (0.7, 1.11) (18, 4) (18, 3.8) (19.7, 3.5) (15.5, 3.82) (0.7, 1.11) (0.7, 1.11) (9.2, 2.23) (18, 3.7)