program 4

Develop a Script in R to produce a bar graph display in the frequency distribution of categorical data in a given dataset, grouped by a specific variable, using ggplot2

#Load necessary libraries
library(ggplot2)

Warning: package 'ggplot2' was built under R version 4.4.3

Step 1: Load the Dataset

We use the built-in mtcars dataset, which contains the information about different car models.

#load dataset
data <- mtcars
#Display first few rows
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 2: Convert Numeric data to Categorical

data$cyl <- as.factor(data$cyl)
data$gear <- as.factor(data$gear)

Step 3: Create a Bar graph

# Create a Bar graph
ggplot(data, aes(x = cyl, fill = gear)) +
  geom_bar(position = "dodge") +
  labs(title = "Frequency of cylinders grouped by Gear Type",
       X = "Number of Cylinders",
       y = "Count",
       fill = "Gears") +
  theme_minimal()