programm 4

4. Develop a script R to produce bar graph displaying the frequency distribution of categorical data in a given dataset, grouped by a specific variable using ggplot2.

Step1: loading necessary libraries

library(ggplot2)

Step2: load dataset

data<-mtcars
head(data)

                   mpg cyl disp  hp drat    wt  qsec vs am gear carb
Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

Step 3:converting numeric data into categorical data

data$cyl<-as.factor(data$cyl)
data$gear<-as.factor(data$gear) #numeric to factor

Step 4: create bar graph

ggplot(data, aes(x=cyl,fill=gear))+
  geom_bar(position="dodge")+
  #dodge:pillars will be side wise
  labs(title="Frequency of cylinders grouped by gear type",
       x="Number of cylinders",
       y="Count",
       fill="Gears")+
  theme_minimal()