PEARSON’S r
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THE INTERACTIVE STATISTICS LAB
Find the pattern.
Question the connection.
Some things move together. That doesn’t always mean they’re connected.
Explore the difference, then put your own numbers to the test.
A relationship worth exploring
Choose a case. Look for a pattern. Ask what could explain it.
Your numbers, every connection
Add sequences of equal length. Values at the same position form a pair.
Number sequences
Separate numbers with commas, spaces, or new lines. Use a dot for decimals; scientific notation is supported.
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THE 30-SECOND GUIDE
Meet the correlation coefficient.
Pearson’s r measures the direction and strength of a linear relationship. It ranges from −1 to +1.
−1 Move in opposite directions0 No linear pattern+1 Move together
Strength is about distance from zero. A negative correlation can be just as strong as a positive one.
A pattern is a starting point. Correlation alone never proves cause and effect. Confounding variables, shared trends, chance, and outliers can all create misleading patterns.
In this lab: |r| ≥ 0.70 is “strong”; |r| ≤ 0.30 is “weak”; values between are “moderate.” These are teaching conventions, not universal rules. A weak Pearson correlation can hide a strong curved relationship.