母体，随机样本。样本统计， 样本平均数和变异数的动差。

Populations, random samples. Sample statistics, moments of the sample mean and variance.

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这些早期研究需要一个长期的平均数作为目标并假设在样本期内影响杠杆的因素维持不变。

This early studies take a long term average as a target and assumes that the factors that influence the leverage remain unchanged over the sample period.

youdao

这些早期研究需要一个长期的平均数作为目标并假设在样本期内影响杠杆的因素维持不变。

This early studies take a long term average as a target and assumes that the factors that influence the leverage remain unchanged over the sample period.

youdao