题目正态曲线下,横轴上在(mu -2.58sigma , mu 2.58sigma )范围内的面积占全部面积的A. 99%B. 95%C. 68.27%D. 90%E. 80%正态曲线下,横轴上在(\mu -2.58\sigma , \mu 2.58\sigma )范围内的面积占全部面积的A. 99%B. 95%C. 68.27%D. 90%E. 80%题目解答答案A. 99%