Residuals versus Fitted Plot
A residuals versus fitted plot is a diagnostic plot for regression models. It graphs residuals against fitted values to assess whether model assumptions look reasonable.
Ideally, the residual cloud should show no clear trend, no curvature, and roughly constant spread. Patterns such as funnel shapes or systematic curves suggest heteroscedasticity or nonlinearity.
This plot is one of the main first checks after fitting a regression model.