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%
12.04%.
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.
老师 请问B是怎么算出来的以及计算器STATA得出的20.02是population的方差吗 我只输入了3个数啊 不应该和样本的SX是一样的吗