Regression diagnostics
Keep X and Y in the same observation order.
Residuals versus fitted values
Look for structure, changing spread and isolated points.
Observation diagnostics
| No. | X | Y | Predicted | Residual | Std. residual | Leverage | Cook D | Flag |
|---|---|---|---|---|---|---|---|---|
| Fill in the fields above — the result is computed on this page. | ||||||||
How to use this page
- Paste paired observations.
- Inspect the residual plot and flagged rows.
What this page does not do: The tool fits one predictor and does not replace subject-matter validation, cross-validation or a full time-series model.
Further reading
Diagnostics identify observations and residual patterns that deserve review after fitting a simple linear model.
Frequently asked questions
Does a flagged point have to be removed?
No. Investigate data quality and model specification first.
See also
A/B test calculator
Compare two proportions in an A/B test. Calculate conversion rates, difference, uplift, z score, p value and c
A/B test planning — sample size, MDE and duration
Plan a two-proportion experiment, estimate detectable effect and traffic duration.
ACF and PACF autocorrelation calculator
Calculate ACF and PACF across time-series lags. Review the chart, reference bounds and coefficient table.