科恩的 D 与 R 中的对比答案

【问题标题】：cohen's D with contrasts in R科恩的 D 与 R 中的对比
【发布时间】：2020-05-18 23:12:12
【问题描述】：

有人可以帮助我了解如何从具有对比的 ANOVA 计算科恩的 D 吗？我从向量或数据集计算科恩的 D 没有问题，但无法从对比中弄清楚如何做到这一点。谢谢。

#Create data frame
group = c("treatment","treatment","treatment","treatment","treatment","treatment","treatment","treatment","treatment","treatment",
          "control","control","control","control","control","control","control","control","control","control",
          "other","other","other","other","other","other","other","other","other","other") 
score = c(7,8,9,10,7,8,9,10,7,8,
          6,5,4,6,5,4,6,5,4,6,
          3,2,1,3,2,1,3,2,1,3) 
sample =data.frame(group,score) 


#Set contrasts
contrast = c(-1,0,1)

#Bind contrasts
contrasts(sample$group) = cbind(contrast)

#Check contrasts
contrasts(sample$group)

#Run ANOVA w/ contrasts 
aov1 = aov(score ~ group, sample)
summary.lm(aov1)

【问题讨论】：

标签： r statistics statistical-test

【解决方案1】：

计算 Cohen 的 D 的函数至少包含在三个不同的 R 包中，包括 effsize、rstatix 和 psych 包。 aov() 函数中没有专门用于计算 Cohen 的 D 的功能。

Cohen 的 D 需要二分组变量。给定 OP 中的数据以及将测试组与对照组进行比较的对比语句，我们将使用psych::cohen.d() 将测试组与对照组进行比较。

group = c("treatment","treatment","treatment","treatment","treatment","treatment","treatment","treatment","treatment","treatment",
          "control","control","control","control","control","control","control","control","control","control",
          "other","other","other","other","other","other","other","other","other","other") 
score = c(7,8,9,10,7,8,9,10,7,8,
          6,5,4,6,5,4,6,5,4,6,
          3,2,1,3,2,1,3,2,1,3) 
sample =data.frame(group,score) 

sample2 <- sample[sample$group != "other",]
sample2$group <- factor(sample2$group)
library(psych)
cohen.d(score ~ group, data = sample2)

...和输出：

> cohen.d(score ~ group, data = sample2)

Cohen's d

d estimate: -3.114651 (large)
95 percent confidence interval:
    lower     upper 
-4.512240 -1.717062

【讨论】：