题目随机变量X的方差D(X)定义为( )A. [E(X)]^2B. E[(X-E(X))^2]C. E(X^2)D. E(X)-[E(X)]^2随机变量X的方差D(X)定义为( )A. [E(X)]^2B. E[(X-E(X))^2]C. E(X^2)D. E(X)-[E(X)]^2题目解答答案B. E[(X-E(X))^2]