##---------------------------------------------------------------------## ## Script for Soc 740 Lecture 6 ## ## John Fox ## ## Winter 2014 ## ##---------------------------------------------------------------------## # Preliminary example library(car) scatterplot(repwt ~ weight|sex, smooth=FALSE, data=Davis) scatterplot(weight ~ repwt|sex, smooth=FALSE, data=Davis) davis.1 <- lm(repwt ~ weight*sex, data=Davis) summary(davis.1) davis.2 <- lm(weight ~ repwt*sex, data=Davis) summary(davis.2) Davis[11:13, ] Davis[12, c(2, 3)] <- Davis[12, c(3, 2)] # correct data Davis[11:13, ] davis.1.fixed <- update(davis.1) summary(davis.1.fixed) # hat-values, studentized residuals, Cook's distances influenceIndexPlot(davis.1) influencePlot(davis.1, id.n=1) influencePlot(davis.1, id.method="identify") outlierTest(davis.1) qqPlot(davis.1, id.n=1) # QQ plot against t(n - k - 2) with simulated envelope # added-variable plots duncan <- lm(prestige ~ income + education, data=Duncan) summary(duncan) avPlots(duncan, id.method="identify") # added-variable plots which.names(c("minister", "conductor"), Duncan) qqPlot(duncan, id.method="identify") duncan.2 <- update(duncan, subset= -c(6, 16)) # removing ministers & conductors summary(duncan.2)