Correlation

Not causation

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• The correlation $r$ (from $-1$ to $1$) measures how well the data fit a straight line.
• Correlation is not causation: watch out for confounding variables.
• Randomized experiments can establish causation.

Steps

1. Scatter plots
2. Ice cream and drowning
3. What r measures
4. A negative correlation
5. Variance explained
6. How to show causation