矩阵形式 n ∑ X ∑ Ⅹ Ⅹ.X ∑ XX XY Xy= ∑X∑xX.∑xx…∑X」 ∑X」 XXB=Xy B=(XX"XY正规方程 矩阵形式 B X X X Y X XB X Y =    =  −1 ( ) ˆ ˆ                =            2 1 2 2 1 1 2 1 1 1 2 ki ki i ki i ki i i ki i i i i i ki X X X X X X X X X X X X n X X X X X                         = bk b b b B ˆ ˆ ˆ ˆ ˆ 2 1 0                 =    ki i i i i X Y X Y Y X Y  1