Why Use Density Plots?

A density plot is a smoothed version of a histogram. It is useful to:

• Understand the distribution of a numeric variable;

• Compare distributions across groups (like fuel types);

• Spot peaks, skewness, and spread.

Unlike histograms, density plots estimate the probability of a value occurring within a range.

Basic Syntax for Density Plots in ggplot2

ggplot(data = df, aes(x = variable)) +
  geom_density()

For group comparisons, use fill = group_variable and adjust transparency using alpha.

Example: Selling Price Distribution

ggplot(df, aes(x = selling_price)) + 
  geom_density(fill = "blue") + 
  labs(title = "Density Plot of Selling Prices", 
       x = "Selling Price", 
       y = "Density")

This plot shows how car prices are distributed, revealing where most prices cluster and how prices are spread.