checking.plots: Checking Plots In PASWR2: Probability and Statistics with R, Second Edition

Description

Function that creates four graphs that can be used to help assess independence, normality, and constant variance

Usage

 1 checking.plots(model, n.id = 3, COL = c("#0080FF", "#A9E2FF"))

Arguments

 model an aov or lm object n.id the number of points to identify COL vector of two colors

Author(s)

Alan T. Arnholt <arnholtat@appstate.edu>

Examples

 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 mod.aov <- aov(stopdist ~ tire, data = TIRE) checking.plots(mod.aov) rm(mod.aov) # Similar graphs using ggplot2 # mod.aov <- aov(stopdist ~ tire, data = TIRE) fortify(mod.aov) # library(gridExtra) used to place all graphs on the same device p1 <- ggplot(data = mod.aov, aes(x = 1:dim(fortify(mod.aov))[1], y = .stdresid, color = tire)) + geom_point() + labs(y = "Standardized Residuals", x = "Ordered Residuals") + geom_hline(yintercept = c(-3,-2, 2, 3), linetype = "dashed", col = "pink") + theme_bw() p2 <- ggplot(data = mod.aov, aes(sample = .stdresid, color = tire)) + stat_qq() + geom_abline(intercept = 0, slope = 1, linetype = "dashed", col = "pink") + theme_bw() p3 <- ggplot(data = mod.aov, aes(x = .fitted, y = .stdresid, color = tire)) + geom_point() + geom_hline(yintercept = 0, linetype = "dashed") + labs(y = "Standardized Residuals", x = "Fitted Values") + geom_hline(yintercept = c(-3, -2, 2, 3), linetype = "dashed", color = "pink") + theme_bw() p1 p2 p3 multiplot(p1, p2, p3, cols = 1) # Or use the following (not run) to get all graphs on the same device # library(gridExtra) # grid.arrange(p1, p2, p3, nrow=3) rm(mod.aov, p1, p2, p3)

PASWR2 documentation built on Sept. 5, 2021, 5:44 p.m.