How does a car’s weight relate to its fuel economy?

The built-in mtcars dataset contains measurements for 32 cars. Each point in the next slide represents one car.

• Weight (wt): thousands of pounds
• Fuel economy (mpg): miles traveled per gallon

Hover over a point to see its weight and fuel economy.

In this dataset, heavier cars generally have lower miles per gallon. The chart shows a relationship, but it does not prove that weight alone caused the difference.