📏 效应量计算器（Cohen's d）Effect Size Calculator (Cohen's d)
输入两组的平均值、标准差和样本量，计算 Cohen's d（合并标准差）、小样本校正的 Hedges' g 和 Glass's Δ，并按 Cohen（1988）的常用基准给出大小参考。Enter the mean, standard deviation and sample size of two groups to get Cohen's d (pooled SD), the small-sample-corrected Hedges' g and Glass's Δ, with Cohen's (1988) conventional benchmarks.
使用说明与常见问题How-to & FAQ
「效应量计算器（Cohen's d）」是什么？What is the Effect Size Calculator (Cohen's d) tool?
输入两组的平均值、标准差和样本量，计算 Cohen's d（合并标准差）、小样本校正的 Hedges' g 和 Glass's Δ，并按 Cohen（1988）的常用基准给出大小参考。Enter the mean, standard deviation and sample size of two groups to get Cohen's d (pooled SD), the small-sample-corrected Hedges' g and Glass's Δ, with Cohen's (1988) conventional benchmarks.
如何使用「效应量计算器（Cohen's d）」？How do I use the Effect Size Calculator (Cohen's d) tool?
在「效应量计算器（Cohen's d）」中，填写「第 1 组平均值」、「第 1 组标准差」、「第 1 组样本量」、「第 2 组平均值」、「第 2 组标准差」等参数，结果会随输入实时计算并显示在下方。In the Effect Size Calculator (Cohen's d): Fill in "Group 1 mean", "Group 1 SD", "Group 1 size", "Group 2 mean", "Group 2 SD"; results are recalculated instantly as you type.
用的是哪些公式？What are the formulas?
合并标准差 sₚ = √(((n₁ − 1)s₁² + (n₂ − 1)s₂²) ÷ (n₁ + n₂ − 2))；d = (M₁ − M₂) ÷ sₚ；Hedges' g = d × (1 − 3 ÷ (4(n₁ + n₂ − 2) − 1))；Glass's Δ = (M₁ − M₂) ÷ s₂，常在第 2 组是对照组时使用。Pooled sₚ = √(((n₁ − 1)s₁² + (n₂ − 1)s₂²) ÷ (n₁ + n₂ − 2)); d = (M₁ − M₂) ÷ sₚ; Hedges' g = d × (1 − 3 ÷ (4(n₁ + n₂ − 2) − 1)); Glass's Δ = (M₁ − M₂) ÷ s₂, used when group 2 is the control.
0.2、0.5、0.8 的基准从哪来？Where do 0.2, 0.5 and 0.8 come from?
来自 Jacob Cohen《Statistical Power Analysis for the Behavioral Sciences》（第 2 版，1988）。他明确说这些只是缺乏领域标准时的约定，不同学科的「大」效应差别很大。From Jacob Cohen, Statistical Power Analysis for the Behavioral Sciences (2nd ed., 1988). He stressed they are conventions for when no field norms exist; what counts as large varies a lot between fields.
d 为负数是什么意思？What does a negative d mean?
第 1 组平均值低于第 2 组。大小看绝对值。Group 1's mean is below group 2's. Judge the size by the absolute value.
计算精度如何？How precise are the results?
「效应量计算器（Cohen's d）」使用 JavaScript 双精度浮点数（约 15–16 位有效数字）；极大或极小的数值可能存在精度误差。The Effect Size Calculator (Cohen's d) uses double-precision floating point (about 15–16 significant digits); very large or very small values may lose precision.
「效应量计算器（Cohen's d）」免费吗？需要注册吗？Is the Effect Size Calculator (Cohen's d) free? Do I need an account?
「效应量计算器（Cohen's d）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Effect Size Calculator (Cohen's d) is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.