Question

求Gmat数学翻译+解题技巧高手！

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

多谢啦！！！！！

Answer 1

某一特性在大人口基数的条件下具有关于平均值M对称的分布，如果68%分布于平均值的一个标准偏差D内，那么分布于小于M+D的概率是多少？

The distribution is symmetric, (因为分布是对称的)
so (所以)
50% of the distribution is less than M (有50%的分布是小于平均值M的)
and (并且)
the distribution between M and M+D is half in one D, (在M与M+D之间的分布是一个标准偏差D内的一半)
68%/2 = 34% of the distribution lies between M and M+D. (即68%/2 = 34%分布于M与M+D之间)
so(所以)
50% + 34% = 84% of the distribution is less than M+D (50% + 34% = 84%分布于小于M+D)

Answer 2

a distribution that is symmetric about the mean M: 50% is less than M
68% of the distribution lies within one standard deviation D of the mean: 34% is between M - D, and 34% is between M and M + D
so 50% + 34% = 84% is less than M + D.