How to Create a Boxplot with Means in R (2 Examples)

data(iris)                                    # Loading iris data
head(iris)
#   Sepal.Length Sepal.Width Petal.Length Petal.Width Species
# 1          5.1         3.5          1.4         0.2  setosa
# 2          4.9         3.0          1.4         0.2  setosa
# 3          4.7         3.2          1.3         0.2  setosa
# 4          4.6         3.1          1.5         0.2  setosa
# 5          5.0         3.6          1.4         0.2  setosa
# 6          5.4         3.9          1.7         0.4  setosa

data(iris) # Loading iris data head(iris) # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 3.5 1.4 0.2 setosa # 2 4.9 3.0 1.4 0.2 setosa # 3 4.7 3.2 1.3 0.2 setosa # 4 4.6 3.1 1.5 0.2 setosa # 5 5.0 3.6 1.4 0.2 setosa # 6 5.4 3.9 1.7 0.4 setosa

iris_means <- aggregate(iris$Sepal.Length,    # Calculate means
                        list(iris$Species),
                        mean)

iris_means <- aggregate(iris$Sepal.Length, # Calculate means list(iris$Species), mean)

boxplot(iris$Sepal.Length ~ iris$Species,     # Draw boxplot with means
        col = 1:3)
points(x = 1:nrow(iris_means),
       y = iris_means$x,
       pch = 16,
       col = "white")
text(x = 1:nrow(iris_means),
     y = iris_means$x + 0.12,
     labels = round(iris_means$x, 2),
     col = "white")

boxplot(iris$Sepal.Length ~ iris$Species, # Draw boxplot with means col = 1:3) points(x = 1:nrow(iris_means), y = iris_means$x, pch = 16, col = "white") text(x = 1:nrow(iris_means), y = iris_means$x + 0.12, labels = round(iris_means$x, 2), col = "white")

install.packages("ggplot2")                   # Install & load ggplot2 package
library("ggplot2")

install.packages("ggplot2") # Install & load ggplot2 package library("ggplot2")

ggplot(iris,                                  # Draw boxplot with means
       aes(x = Species,
           y = Sepal.Length,
           fill = Species)) +
  geom_boxplot() +
  stat_summary(fun = mean,
               col = "white",
               geom = "point") +
  stat_summary(fun = mean,
               col = "white",
               geom = "text",
               vjust = - 1,
               aes(label = round(..y.., digits = 2)))

ggplot(iris, # Draw boxplot with means aes(x = Species, y = Sepal.Length, fill = Species)) + geom_boxplot() + stat_summary(fun = mean, col = "white", geom = "point") + stat_summary(fun = mean, col = "white", geom = "text", vjust = - 1, aes(label = round(..y.., digits = 2)))