Add Significance Levels to ggplot2 Plot Using ggsignif Package in R (Example Code)

data(iris)                       # Load example 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) # Load example 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

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

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

my_ggplot <- ggplot(iris,        # Drawing a regular ggplot2 boxplot
                  aes(x = Species,
                      y = Sepal.Length)) +
  geom_boxplot()
my_ggplot

my_ggplot <- ggplot(iris, # Drawing a regular ggplot2 boxplot aes(x = Species, y = Sepal.Length)) + geom_boxplot() my_ggplot

install.packages("ggsignif")     # Install & load ggsignif
library("ggsignif")

install.packages("ggsignif") # Install & load ggsignif library("ggsignif")

my_ggplot +                      # Adding significance stars
  geom_signif(comparisons = list(c("setosa", "versicolor"),
                                 c("setosa", "virginica")),
              map_signif_level = TRUE,
              y_position = c(8, 9))

my_ggplot + # Adding significance stars geom_signif(comparisons = list(c("setosa", "versicolor"), c("setosa", "virginica")), map_signif_level = TRUE, y_position = c(8, 9))