Mathematics I / Descriptive Statistics
Practice question · Multiple choice

Anscombe's quartet is four datasets with identical means, variances, correlation and regression line, and wildly different shapes. What was Anscombe demonstrating?

Hints
  1. All four have correlation 0.816. Ask what the four scatterplots look like.
  2. One is a clean line, one a perfect curve, one has a single outlier doing all the work.
Show the answer

A. That identical summaries can describe completely different data

Why

Same numbers, four different worlds: a linear relationship, a parabola, an outlier dragging the line, and a single leverage point. The summaries are correct and insufficient, which is why 'plot it first' is methodological advice rather than aesthetic preference.

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