Diagnostic plots for linear models

Generates a set of three diagnostic plots for a linear model object, side by side: Residuals vs Fitted (checks linearity and constant variance), Normal Q-Q (checks normality of residuals), and residuals in data order (checks independence). Use it right after fitting a model to check the regression assumptions in one call instead of building each plot yourself. Graphical parameters (mfrow) are restored on exit.

Usage

diagnose(model)

Arguments

model

An object of class lm.

Value

None. The function is called for its side effect of producing plots.

Examples

# Simple regression
diagnose(lm(mpg ~ wt, data = mtcars))


# Works the same for multiple regression
diagnose(lm(mpg ~ wt + hp + disp, data = mtcars))


# A poorly-specified model shows curvature in Residuals vs Fitted
diagnose(lm(dist ~ speed, data = cars))