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Victoriazhang · 2021年08月09日

可以求解下这道题的详细解题过程么 列公式计算的那种

NO.PZ2017092702000156

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.


可以求解下这道题的详细解题过程么 列公式计算的那种

1 个答案

星星_品职助教 · 2021年08月09日

同学你好,

类似本题这种的计算方差/标准差,我们并不用公式解,而是用计算器直接按。

计算器背后的公式原理是这两个:

计算出样本均值为14.67%后,n=3,将数字逐个代入红框内的公式计算出样本方差,然后开方就可以了(“%”当做单位处理,可以不用写进去)。

了解一下原理就行,正常也不会用公式去算的。