Regression Lab
Fit an ordinary least squares line to any pair of columns and get the diagnostics that decide whether the fit means anything: residual plot, R², standard errors, and leverage.
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About this tool
Fitting the line is the easy part and every tool does it. What decides whether you can use the line is the residual plot, and most tools bury it. Here it sits directly under the fit, at the same width, on the same x-scale, so the fan shape or the curve is impossible to miss.
Worth knowing
- Look at the residuals before you look at R². A high R² with structured residuals is a warning, not a result.
- Points with high leverage are ringed. One of them is usually doing most of the work.
- Try a log transform on a skewed x. Watch the residual plot go flat.