Correlation summary

Key learning points

• Sign of association from the slope of the cloud.
• Product-moment coefficient $r\in[-1,1]$.
• Outliers can distort $r$.
• Correlation is not causation.

Worked example 1 — Interpret r

What does $r=0.92$ suggest?

Working

Still inspect the scatter for non-linearity or outliers.

Worked example 2 — Sign of association from the slope of the cloud

Use this method from the Correlation sheet: Sign of association from the slope of the cloud.

Working

Each key learning point matches a question type on the printable worksheet.

Worked example 3 — Product-moment coefficient

Use this method from the Correlation sheet: Product-moment coefficient $r\in[-1,1]$.

Working

Each key learning point matches a question type on the printable worksheet.

Worked example 4 — Outliers can distort

Use this method from the Correlation sheet: Outliers can distort $r$.

Working

Each key learning point matches a question type on the printable worksheet.

Worked example 5 — Correlation is not causation

Use this method from the Correlation sheet: Correlation is not causation.

Working

Each key learning point matches a question type on the printable worksheet.

Scaffolded Learning Sheet and answers (PDFs)

This page is a short, searchable overview for revision and search engines. Use the Scaffolded Learning Sheet first, then the Answers PDF for a full written solution. The printable PDFs remain the main classroom resource.