bai kt1

data(iris)
aggregate(
  Sepal.Length ~ Species,
  data = iris,
  FUN = function(x) c(
    min = min(x),
    max = max(x),
    median = median(x)
  )
)

##      Species Sepal.Length.min Sepal.Length.max Sepal.Length.median
## 1     setosa              4.3              5.8                 5.0
## 2 versicolor              4.9              7.0                 5.9
## 3  virginica              4.9              7.9                 6.5

library(ggplot2)

ggplot(iris, aes(x = Species, y = Sepal.Length, fill = Species)) +
  stat_summary(fun = mean, geom = "col") +
  labs(
    title = "Giá trị trung bình Sepal.Length theo từng nhóm Species",
    x = "Species",
    y = "Mean Sepal.Length"
  ) +
  theme_minimal()