mtcars Dataset Visualization

Introduction

In this assignment, we explore the mtcars dataset, which contains information about various car models.

mpg: Miles per gallon (Numeric)

cyl: Number of cylinders (Numeric)

disp: Displacement Numeric cubic (inches)

hp: Gross horsepower Numeric (hp)

drat: Rear axle ratio Numeric (ratio)

wt: Weight Numeric (1000 lbs)

qsec:1/4 mile time Numeric (seconds)

vs V/S engine (0 = V-shaped, 1 = straight) Numeric (binary)

am Transmission (0 = automatic, 1 = manual) Numeric (binary)

gear Number of forward gears Numeric (gears)

carb Number of carburetors Numeric (carburetors)

#install.packages("tidyverse")

library(tidyverse) # Load the tidyverse package for data manipulation and visualization

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library(ggplot2) # Load ggplot2 for creating plots

# Load the mtcars dataset (built into R)
data_mtcars <- mtcars

# View the first few rows to understand the data
head(data_mtcars)

# Convert 'am' (transmission type) and 'cyl' (number of cylinders) to factors for categorical plotting
data_mtcars$am <- as.factor(data_mtcars$am)
data_mtcars$cyl <- as.factor(data_mtcars$cyl)

Scatter Plot

# Create a scatter plot of car weight vs. miles per gallon, colored by cylinder count
ggplot(data_mtcars, aes(x = wt, y = mpg, color = cyl)) +
  geom_point() + # Add points to the plot
  labs(title = "Weight vs. Miles Per Gallon", x = "Weight (1000 lbs)", y = "Miles Per Gallon") # Add plot labels

Line Graph

#Create a line graph of ordered mpg by the row number.
data_mtcars_line <- data_mtcars %>% mutate(index = row_number()) #add index column so we can plot it

ggplot(data_mtcars_line, aes(x = index, y = mpg)) +
  geom_line() + # add a line to the plot
  labs(title = "Miles Per Gallon by Index", x = "Index", y = "Miles Per Gallon") # add plot labels

Horizontal Bar Chart

# Create a horizontal bar chart of the average horsepower grouped by cylinder count
hp_by_cyl <- data_mtcars %>% group_by(cyl) %>% summarize(avg_hp = mean(hp)) # Calculate average horsepower for each cylinder group

ggplot(hp_by_cyl, aes(y = cyl, x = avg_hp)) +
  geom_bar(stat = 'identity') + # Create bars based on the calculated averages
  labs(title = "Average HP by Cylinder Count", y = "Cylinder Count", x = "Average Horsepower") # Add plot labels

Stacked Bar Chart

#Create a stacked bar chart of average mpg, disp, hp, and wt, grouped by cyl.
bar_data_mtcars <- data_mtcars %>% group_by(cyl) %>% summarize(mpg = mean(mpg), disp = mean(disp), hp = mean(hp), wt = mean(wt)) %>% pivot_longer(cols = c("mpg", "disp", "hp", "wt"), names_to = "Measurement", values_to = "Average") #Calculate average values for each measurement, and pivot the data into a long format.

ggplot(bar_data_mtcars, aes(x = cyl, fill = Measurement, y = Average)) +
  geom_bar(stat = "identity") + #Create bars based on the calculated averages
  labs(title = "Average Measurements by Cylinder Count", x = "Cylinder Count", y = "Average Measurement") #add plot labels