两模型y与x1,x2关系的比较 y=Po+Bx+B2x2+B3x2 y=Bo+Bx+B2x2+B3-x2+4xx2 9 9 8.5 8.5 x2=6.5 8 7.5 -0.2 0.2 04 0.6 75 -0.2 0.2 0.4 0.6 10.5 9.5 x1=0,295 8.5 9 8.5 7.5 7 8 8 8x2=6.5 x1=0.2 -0.2 0 0.2 0.4 0.6 7.5 8 8.5 9 x1 y ˆ -0.2 0 0.2 0.4 0.6 7.5 8 8.5 9 x1 y ˆ 5 6 7 8 7.5 8 8.5 9 9.5 10 x2 y ˆ 5 6 7 8 8 8.5 9 9.5 10 10.5 x2 y ˆ 2 0 1 1 2 2 3 2 ˆ ˆ ˆ ˆ y ˆ =  +  x +  x +  x 4 1 2 2 0 1 1 2 2 3 2 ˆ ˆ ˆ ˆ y ˆ =  +  x +  x +  x +  x x 两模型 y ˆ 与x1,x2关系的比较