由(202)=(2)2aw limL(,2)=0 iL(x,2)=0imL(u,a2)=0 →∞ >0 =xa2=∑(x-x)2 n i=1 是L(μ,a2)的最大值点.∴μ和G的极大似然估 计量是 =Fa21 ∑(X;-X 1i=1 回民是L(, 2)的最大值点. ∴ 和 2的极大似然估 计量是 = =  − = n i Xi X n X 1 * 2* 2 ( ) 1    = = − − − n i i n x L e 1 2 2 ( ) 2 1 2 2 ( , ) (2 )   由     lim ( , ) 0 lim ( , ) 0 lim ( , ) 0 2 0 2 2 2 2 = =  = → → →          L L L  = =  − = n i i x x n x 1 * 2* 2 ( ) 1  