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标题: [求助]请教一道数学题 [打印本页]

作者: simonshen 时间: 2007-7-6 01:00
标题: [求助]请教一道数学题

请教各位一道数学题,关于标准偏差的,这个好像中国的中学里都不怎么教,所以不太懂.

A certain characteristic in a large population has a distribution that is symmetric about the mean m. If 68% of the distribution lies within one standard deviation d of the mean, what percent of the distribution is less than m + d ?

A 16%

B 32%

C 48%

D 84%

E 92%

作者: meggie_xm 时间: 2007-7-6 02:15
84%，lz可以考虑用正态分布的图形做就更简单了，我就用正态分布的图形做地

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