This dataset contains a subset of the fuel economy data from the EPA. Specifically, we use the mpg dataset from the ggplot2 package.

The visualization Figure 1 shows a positive, strong, and linear relationship between the city and highway mileage of these cars. Additionally, mileage is higher for cars with fewer cylinders.

Code 
ggplot(mpg, aes(x = hwy, y = cty, color = cyl)) +
  geom_point(alpha = 0.5, size = 2) +
  scale_color_viridis_c() +
  theme_minimal()

Scatterplot of city vs. highway mileage for cars, where points are colored by the number of cylinders. The plot displays a positive, linear, and strong relationship between city and highway mileage, and mileage increases as the number of cylinders decreases.

Figure 1: City and highway mileage for 38 popular models of cars.

test

Code 
print(2^3)
[1] 8

second figure …: Figure 2

Code 
ggplot(mpg, aes(x = hwy, y = cty, color = displ)) +
  geom_point(alpha = 0.5, size = 2) +
  scale_color_viridis_c(option = "E") +
  theme_minimal()

Figure 2: ?(caption)

third, in columns: see Figure 3

Code 
ggplot(mpg, aes(x = hwy, y = cty, color = cyl)) +
  geom_point(alpha = 0.5, size = 2) +
  scale_color_viridis_c() +
  theme_minimal()

ggplot(mpg, aes(x = hwy, y = cty, color = displ)) +
  geom_point(alpha = 0.5, size = 2) +
  scale_color_viridis_c(option = "E") +
  theme_minimal()

(a) Color by number of cylinders

(b) Color by engine displacement, in liters

Figure 3: City and highway mileage for 38 popular models of cars.