outlier tagging boxplot r
library(dplyr)
library(ggplot2)
is_outlier <- function(x) {
return(x < quantile(x, 0.25) - 1.5 * IQR(x) | x > quantile(x, 0.75) + 1.5 * IQR(x))
}
mtcars %>%
group_by(cyl) %>%
mutate(outlier = ifelse(is_outlier(drat), drat, as.numeric(NA))) %>%
ggplot(., aes(x = factor(cyl), y = drat)) +
geom_boxplot() +
geom_text(aes(label = outlier), na.rm = TRUE, hjust = -0.3)