PROGRAM 12

Author

PRACHETAN MS

Objective

To generate a basic box plot using ggplot2,enhanced with notches and outliers, and grouped by a categorical variable using an in built dataset in R.

Step 1: Load required package

We use the ggplot2 package for data visualization

#install.packages("ggplot2") # Uncomment if needed
library(ggplot2)
Warning: package 'ggplot2' was built under R version 4.5.3

Step 2: Use an inbuilt dataset We will use the built-in iris dataset.This dataset

#load and preview the dataset
data(iris)
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
str(iris)
'data.frame':   150 obs. of  5 variables:
 $ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
 $ Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
 $ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
 $ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
 $ Species     : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...

Step 3: Create a Violin Plot

We create a violin plot for Sepal.Length grouped by Species.

ggplot(iris, aes(x = Species,y = Sepal.Length))

ggplot(iris, aes(x = Species,y = Sepal.Length)) +
  geom_violin(
    notch = TRUE,
    notchwidth = 0.6,
    outlier.colour = "red",
    outlier.shape = 16,
    fill = "skyblue",
    alpha = 0.7
    )
Warning in geom_violin(notch = TRUE, notchwidth = 0.6, outlier.colour = "red", : Ignoring unknown parameters: `notch`, `notchwidth`, `outlier.colour`, and
`outlier.shape`

ggplot(iris, aes(x = Species,y = Sepal.Length)) +
  geom_violin(
    fill = "green", alpha = 0.7) +
  labs(
    title = "Sepal length distribution by iris Species",
    subtitle = "Box plot with notches and outlier highlighting",
    x = "Species",
    y = "Petal.Width (cm)"
  ) +
  theme_minimal()

ggplot(iris, aes(x = Species, y = Sepal.Length, fill = Species)) +
  geom_violin(alpha = 0.7) +
  labs(
    title = "Sepal Length Distribution by Iris Species",
    subtitle = "Violin Plot with Legend",
    x = "Species",
    y = "Sepal Length (cm)",
    fill = "Species"   # Legend title
  ) +
  theme_minimal()