program 6

Write an R script to construct a box plot showcasing the distribution of a continuous variable,grouped by a categorical variable,using ggplot2’s fill aesthetic .

step 1: load required library

library(ggplot2)

step 2 :Explore the inbuilt dataset

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 ...

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

step 3: construct box plot with grouping

step 3.1:initialize ggplot with aesthetic mappings

p <- ggplot(data = iris,aes(x=Species,y= Petal.Width,fill = Species))

step 3.2:Add Box Plot Layer

p <- p + geom_boxplot()

step 3.3:Add Labels and theme

p <- p + labs(title ="Box Plot of Petal Width by Species ",
              x="Species",
              y="Petal Width")+
  theme_minimal()

step 3.4:Display the plot

p