SQL-STDEVP或STDEV以及如何使用? [英] SQL - STDEVP or STDEV and how to use it?

问题描述

我有一张桌子:

LocationId OriginalValue Mean
1          0.45         3.99  
2          0.33         3.99
3          16.74        3.99
4          3.31         3.99

以此类推...

我如何使用此表计算Standard Deviation，还有您的建议-STDEVP或STDEV?

How would I work out the Standard Deviation using this table and also what would you recommend - STDEVP or STDEV?

推荐答案

要使用它，只需:

SELECT STDEVP(OriginalValue)
FROM yourTable

在下面，您可能需要STDEVP.

从此处 :

STDEV 用于当被评估的数字组仅是整个人群的部分抽样时.用于除以平方差之和的分母为N-1，其中N为观察数(数据集中项目的计数).从技术上讲，减去1称为无偏".

STDEV is used when the group of numbers being evaluated are only a partial sampling of the whole population. The denominator for dividing the sum of squared deviations is N-1, where N is the number of observations ( a count of items in the data set ). Technically, subtracting the 1 is referred to as "non-biased."

STDEVP 是在要评估的一组数字完成时使用的-它是值的整个种群.在这种情况下，不减去1，并且用于除以平方偏差总和的分母就是N本身，即观察数(数据集中的项计数).从技术上讲，这被称为偏置".记住STDEVP中的P代表人口".可能会有所帮助.由于数据集不仅仅是一个样本，而是由所有实际值组成，因此该标准偏差函数可以返回更精确的结果.

STDEVP is used when the group of numbers being evaluated is complete - it's the entire population of values. In this case, the 1 is NOT subtracted and the denominator for dividing the sum of squared deviations is simply N itself, the number of observations ( a count of items in the data set ). Technically, this is referred to as "biased." Remembering that the P in STDEVP stands for "population" may be helpful. Since the data set is not a mere sample, but constituted of ALL the actual values, this standard deviation function can return a more precise result.

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