MihsabaHow to use
Pearson’s r measures the direction and strength of a linear relationship between paired numeric series. The tool returns r, r², a simple regression line and basic statistics, but does not interpret correlation as causation.
- Enter X values separated by spaces or commas.
- Enter Y values with the same count and pairing order.
- Calculate.
- Review r, r², regression line and pair count.
How it is calculated
r=Σ[(x−x̄)(y−ȳ)]÷√[Σ(x−x̄)²Σ(y−ȳ)²]
Example
For X=[1,2,3,4] and Y=[2,4,6,8], r=1, a perfect positive linear relationship, and the regression line is y=2x.
Important notes
Pearson measures linear association and is sensitive to outliers. r near zero does not rule out a nonlinear relationship, and correlation does not prove causation.
Frequently asked questions
What is the range of r?
From -1 to +1.
What does r² mean?
The squared correlation; in simple linear regression it is the coefficient of determination.
Does correlation imply causation?
No.
Is this calculator free?
Yes. It is free to use and requires no account.