Scatter plots (geom_point) in R Programming - Mini Project: Build & Apply

Scatter plots (geom_point)

📖 Scenario: You are a data analyst working with a small dataset of car speeds and stopping distances. You want to visualize the relationship between speed and distance using a scatter plot.

🎯 Goal: Create a scatter plot using geom_point in ggplot2 to show how car speed relates to stopping distance.

📋 What You'll Learn

Create a data frame called cars_data with columns speed and dist using the exact values provided.

Create a variable called plot_title with the exact string 'Speed vs Stopping Distance'.

Use ggplot with geom_point to create a scatter plot of speed on the x-axis and dist on the y-axis.

Add the title stored in plot_title to the plot using ggtitle().

Print the plot object to display the scatter plot.

💡 Why This Matters

🌍 Real World

Scatter plots help visualize relationships between two numeric variables, such as speed and stopping distance in cars.

💼 Career

Data analysts and scientists use scatter plots to explore data patterns and communicate findings clearly.

1

Create the data frame

Create a data frame called cars_data with two columns: speed containing the values 4, 7, 8, 9, 10 and dist containing the values 2, 10, 15, 20, 25.

R Programming

# Create the data frame cars_data with speed and dist columns
# Your code here

Need a hint?

Use data.frame() with speed = c(...) and dist = c(...) to create the data frame.

2

Add a plot title variable

Create a variable called plot_title and assign it the string 'Speed vs Stopping Distance'.

R Programming

cars_data <- data.frame(
  speed = c(4, 7, 8, 9, 10),
  dist = c(2, 10, 15, 20, 25)
)
# Create the plot_title variable
# Your code here

Need a hint?

Assign the exact string to plot_title using the assignment operator <-.

3

Create the scatter plot

Use ggplot with the data frame cars_data. Map speed to the x-axis and dist to the y-axis. Add geom_point() to create the scatter plot points.

R Programming

cars_data <- data.frame(
  speed = c(4, 7, 8, 9, 10),
  dist = c(2, 10, 15, 20, 25)
)
plot_title <- 'Speed vs Stopping Distance'

# Create the ggplot object with geom_point
# Your code here

Need a hint?

Use ggplot(data, aes(x = ..., y = ...)) + geom_point() to create the scatter plot.

4

Add title and display the plot

Add the title stored in plot_title to the plot using ggtitle(plot_title). Then print the plot object to display the scatter plot.

R Programming

library(ggplot2)
cars_data <- data.frame(
  speed = c(4, 7, 8, 9, 10),
  dist = c(2, 10, 15, 20, 25)
)
plot_title <- 'Speed vs Stopping Distance'

plot <- ggplot(cars_data, aes(x = speed, y = dist)) + geom_point()

# Add the title and print the plot
# Your code here

Need a hint?

Use plot + ggtitle(plot_title) to add the title, then print(plot) to show the plot.