what is a function in r that is a residual which lm is r in the derivation of $var(hatvarepsilon)$, why did the term $(1-h)xbeta$ vanish? where did it go? what is the derivation of residuals in the r lm diagnostic plot what is the purpose of the residual term in r diagnostics? what is the point of r lm diagnostics what is the definition of residuals what is the logical function of residuals in r which term did the term $(1-H)xbeta$ vanish? where did it go? what is the derivation of residuals for r diagnostic plots what is the definition of residual what is the derivation of residuals what is the definition of lm diagnostics what is the purpose of the residuals in diagnostic plot? what does a residual value represent in R when derivation of residuals in r lm diagnostics what does it mean define the term $(1-h)x+beta what is the step in derivation what step in r lm diagnostics will be explained? why does the term $(1-H)Xbeta$ vanish in the derivation of $var(hatvarepsilon)$