histogram.cohensD(other)

• other <Histogram> 用来比较的直方图。
• 返回：<number> 效应大小

计算 科恩的d 的效应量，即这个直方图与 other 平均值之间的标准化差异，使用合并标准差。正值表示这个直方图的平均值更高。按照惯例，|d| < 0.2 属于小效应，0.5 属中等效应，0.8 或以上属于大效应。两个直方图都必须至少有 2 个记录值，否则返回 0。

🌐 Computes Cohen's d effect size, the standardized difference between the means of this histogram and other, using the pooled standard deviation. Positive values indicate this histogram has a higher mean. By convention, |d| < 0.2 is a small effect, 0.5 is medium, and 0.8 or greater is large. Both histograms must have at least 2 recorded values; otherwise returns 0.