CurriculumGrade 9Mathematics

Correlation vs. Causation

Aligned to S-ID.C.9 — Common Core State Standards for Mathematics.

What this lesson teaches

Two variables can be correlated without one causing the other — a hidden third factor or pure coincidence may link them. Only a controlled experiment can establish cause.

Worked example

Ice cream sales and drowning both rise together, so they are correlated. But ice cream does not cause drowning; hot weather is the hidden factor that raises both.

Practice questions

  1. Give an example of two correlated things where neither causes the other.
  2. Shoe size correlates with reading level in children. What hidden factor explains it?
  3. Why can't correlation alone prove that one variable causes another?

Watch the lesson

Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.

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En español

Correlación vs. Causalidad

Dos variables pueden estar correlacionadas sin que una cause la otra: un tercer factor oculto o pura coincidencia puede relacionarlas. Solo un experimento controlado puede establecer la causa.

Ejemplo: Las ventas de helado y los ahogamientos suben juntos, así que están correlacionados. Pero el helado no causa ahogamientos; el calor es el factor oculto que aumenta ambos.

More Statistics & Probability lessons

Displaying DataS-ID.A.1Comparing Center and SpreadS-ID.A.2Outliers and Their EffectS-ID.A.3Two-Way Frequency TablesS-ID.B.5Slope and Intercept in DataS-ID.C.7The Correlation CoefficientS-ID.C.8

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