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努力奋斗小小张 · 2021年06月01日

问一道题:NO.PZ2017092702000156 [ CFA I ]

问题如下:

Using the information in the following table, the sample standard deviation for VWIGX is closest to:

选项:

A.

6.02%

B.

12.04%.

C.

24.54%

解释:

C is correct. The sample variance is defined as sum of the squared deviations from the sample mean divided by the sample size minus one, and the sample standard deviation equals the square root of the sample variance.

The sample variance is thus equals to 6.02. The square root of the sample variance is the sample standard deviation and equals to 24.54%.

A is incorrect because it is the sample variance for VWGIX, not its sample standard deviation.
B is incorrect because it represents the sum of the squared deviations from the mean, not the sample standard deviation.


我用计算器输出方差是24.53%.不是求平方根吗,具体什么思路啊

3 个答案

星星_品职助教 · 2021年06月01日

@张笑-休假中 Sx是样本标准差的意思,本题求的就是“sample standard deviation”

努力奋斗小小张 · 2021年06月01日

我的意思是这个Sx是方差,这个题目不是应该是标准差吗,应该在这个基础上再开方吧?

星星_品职助教 · 2021年06月01日

同学你好,

24.53%没有问题。

2nd+7输入计算器后,2nd+8找到Sx=24.5316(%),这就是答案,本题求的就是“sample standard deviation”