题目正态分布曲线下,从2σ范围内的面积A. 95.00%B. 95.45%C. 99.73%D. 68.27%正态分布曲线下,从2σ范围内的面积A. 95.00%B. 95.45%C. 99.73%D. 68.27%题目解答答案B. 95.45%