Question

这是一道GRE数学题，题没读懂，求大神帮忙解答一下

The distribution of the numbers of hours that students at a certain college studied for final exams has a mean of 12 hours and a standard deviation of 3 hours. Which of the following numbers of hours are within 2 standard deviations of the mean of the distribution? Indicate all such numbers
A.2 B.5 C10 D.14 E.16

Answer 1

答案选CDE

追问

麻烦给下解答思路呗

追答

大致意思是学生为学习，学习时间平均为12小时，一个标准区间是3小时。问以下哪些时间处于平均时间加减2个标准区间内

这个就是高斯分布的概念题啦，就是看在12-2×3=6和12+2×3=18，看看哪些选项在6到18之间啦

Answer 2

关于GRE题目的问题可以去新东方在线论坛求助哦，上面有很多考过的小伙伴