kt

data(iris)

ket_qua <- aggregate(
  Sepal.Width ~ Species,
  data = iris,
  FUN = function(x) c(
    Nho_nhat = min(x),
    Lon_nhat = max(x),
    Do_lech_chuan = sd(x)
  )
)

ket_qua

##      Species Sepal.Width.Nho_nhat Sepal.Width.Lon_nhat
## 1     setosa            2.3000000            4.4000000
## 2 versicolor            2.0000000            3.4000000
## 3  virginica            2.2000000            3.8000000
##   Sepal.Width.Do_lech_chuan
## 1                 0.3790644
## 2                 0.3137983
## 3                 0.3224966

library(ggplot2)

ggplot(iris, aes(x = Species, y = Sepal.Length)) +
geom_boxplot(fill = "lightblue") +
labs(
title = "Boxplot Sepal.Length theo Species",
x = "Species",
y = "Sepal.Length"
) +
theme_minimal()