王 王令x=∑X,x=n∑X j=1 则s,=∑(x2-x)=(x1-+-x) xx-x}+x+立xX-x j=1 ∑(x2x)+∑(xx 其中交叉乘积项 c22∑(X-XXx-x)=2(X-X∑(X0-x,) J =2∑(X,-X)X-t1,)=0 上页  = = = = = − = − + − r i n j i j i i r i n j T i j i i S X X X X X X 1 1 2 1 1 2 则 ( ) ( . . ) 其中交叉乘积项    = = = = − − = − − i ni j i j i r i i i r i n j Xi j Xi X X X X X X 1 1 1 1 2 ( .)( . ) 2 ( . ) ( .)   = = = = i ni j i j i i n j i i j X n X X X 1 1 1 令 . , .   = = = = − + − r i i i r i n j Xi j Xi n X X i 1 2 2 1 1 ( .) ( . ) 2 ( . )( . .) 0 1 =  − − = = i i r i Xi X X tX ( .) ( . ) 2 ( .)( . ) 1 1 1 1 2 1 1 2 X X X X X X Xi X r i n j i j i r i n j i r i n j i j i i i i = − + − +  − − = = = = = =