Calculator Uni

Correlation Calculator

Measure the Pearson correlation between two paired data sets.

Paired data

Pearson correlation (r)

0.9157

strong positive

r² (variance explained)

83.9%

Pairs

6

Reading r

Pearson's r runs −1 to +1, measuring how tightly points hug a straight line: +1 perfect rise, −1 perfect fall, 0 no linear pattern. Squaring it gives the share of one variable's variance the other explains — r = 0.7 explains about half.

The two classic caveats

Correlation isn't causation — ice cream sales and drownings correlate through summer. And r only sees straight lines: a perfect U-shaped relationship scores near zero. Always plot the data before trusting the number.

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