Step by Step Procedure to calculate Cohen’s d in R

Method 1: Calculate Cohen’s d in R using lsr

Step 1: Package Installation

install.packages("lsr")
library(lsr)

Step 2: Creating Data Set

group1 <- c(21, 20, 18, 16, 12, 14, 15, 16, 11, 11, 9, 8)
group2 <- c(23, 20, 16, 10, 11, 11, 12, 14, 14, 10, 9, 7)

Step 3: Calculate Cohen’s d

cohensD(group1, group2)

Output:

0.2635333

Using the rule of thumb mentioned earlier, we would interpret this to be a small effect size.

Method 2: Calculate Cohen’s d in R using effsize

Step 1: Package Installation

install.packages("effsize")
library(effsize)

Step 2: Creating Data Set

group1 <- c(21, 20, 18, 16, 12, 14, 15, 16, 11, 11, 9, 8)
group2 <- c(23, 20, 16, 10, 11, 11, 12, 14, 14, 10, 9, 7)

Step 3: Calculate Cohen’s d

cohen.d(group1, group2)

Output:

d estimate: 0.2635333 (small)
95 percent confidence interval:
lower upper
-0.5867889 1.1138555

Using the rule of thumb mentioned earlier, we would interpret this to be a small effect size.

In this article, we will discuss what is Cohen’s d and how to Calculate Cohen’s d in R Programming Language.