Put whisker ends on boxplot

Question

I would like to put perpendicular lines at the ends of the whiskers like the boxplot function automatically gives.

Answer 1

To resize the whiskers lines we can use the argument width = 0.5 inside the function: stat_boxplot

set.seed(42)
df <- data.frame(cond = factor(rep(c("A", "B"), each = 500)), 
                 value = c(rnorm(500, mean = 1, sd = 0.2), 
                           rnorm(500, mean = 1.5, sd = 0.1))) 

library(ggplot2)
ggplot(df, aes(x = cond, y = value)) +
       stat_boxplot(geom = "errorbar", width = 0.5) +  
       geom_boxplot()