题目9.设随机变量 sim N(2,(sigma )^2) ,已知 (2leqslant Xleqslant 4)=0.4 ,则 (Xleqslant 0)=()-|||-(A)0.1 (B)0.2 (C)0.4 (D)0.6题目解答答案D. 0.6
