1.效应量（effect size）：表示两个分布的重叠程度，它反映研究中处理效应的大小。效应量不受样本量影响。

• Indicates the degree of overlap between the two distributions, which reflects the size of the treatment effect in the study. The effect size is not affected by the sample size.

2.相关样本t检验的效应量＝差异样本均值/差异样本方差

• Effect size for correlated samples t-test = difference sample mean/difference sample variance

即Cohen's d = ES =

两个相关样本差异的95%置信区间为：

研究结果的统计效力、效应大小、样本容量以及显著性水平相互联系。当显著性水平为0.05时，统计效力与效力大小、样本容量的关系如表所示。