概率伦与款醒统外「 则随机变量之和的标准化变量 x-2x2x-24 k=1 2x B 的分布函数F(x)对于任意x满足 ∑x-∑4 lim F((x)=lim P每 k=1 ≤X〉 则随机变量之和的标准化变量             − =    = = = n k k n k k n k k n D X X E X Z 1 1 1 n n k k n k k B X  = = − = 1 1  的分布函数Fn (x)对于任意x满足                − =   = = → → x B X F x P n n k k n k k n n n 1 1 lim ( ) lim  − − = = x t e dt (x). 2π 1 2 2 