Diagnostic plots for fitted values.
References
Fox, John (1991), Regression Diagnostics. Newbury Park, CA: Sage Publications.
Cook, R. D. and Weisberg, S. (1982), Residuals and Influence in Regression, New York: Chapman & Hall.
See also
Other diagnostic plots:
blr_plot_diag_influence()
,
blr_plot_diag_leverage()