Eln(a5+b)]2 E(n-En+ae(s-Es+(En-aEs-b) 2aE[(n}Em)(-E)] p(,7) E[(7-Em)-E) ()a() E[-(a5+b)]=a(m)+ao2() -2ap(,m)(2)o(n)+(E7-aE2-b)2 O a-(5,)Q(m +a2()1-p2(,m+(En-aE+b)2 2021/2/202021/2/20 10 E[h-(ax+b)]2 =E(h-Eh) 2+a 2E(x-Ex) 2+(Eh-aEx-b) 2 -2aE[(h-Eh)(x-Ex)]. [( )( )] ( , ) . (1) ( ) ( ) E E E h h x x  x h s x s h - - = 2 2 2 2 2 2 2 2 2 2 [ ( )] ( ) ( ) 2 ( , ) ( ) ( ) ( ) ( ) ( ) ( , ) ( ) ( )[1 ( , )] ( ) E a b a a E aE b a E aE b h x s h s x  x h s x s h h x s h s x  x h s x s h  x h h x - + = + - + - -   = -     + - + - -