Preface to First Edition - lib

ANALYSIS USING R 551 R> layout(matrix(c(1,2,1,3), nrow = 2, ncol = 2, byrow = FALSE))2 R> boxplot(I(width * convert) ~ unit, data = roomwidth,3 + ylab = "Estimated width (feet)",4 + varwidth = TRUE, names = c("Estimates in feet",5 + "Estimates in metres (converted to feet)"))6 R> feet qqnorm(roomwidth$width[feet],8 + ylab = "Estimated width (feet)")9 R> qqline(roomwidth$width[feet])10 R> qqnorm(roomwidth$width[!feet],11 + ylab = "Estimated width (metres)")12 R> qqline(roomwidth$width[!feet])Estimated width (feet)20 40 60 80 100Estimates in feetEstimates in metres (converted to feet)Normal Q−Q PlotNormal Q−Q PlotEstimated width (feet)30 50 70 90Estimated width (metres)10 15 20 25 30 35 40−2 −1 0 1 2Theoretical Quantiles−2 −1 0 1 2Theoretical QuantilesFigure 3.1Boxplots of estimates of room width in feet and metres (after conversionto feet) and normal probability plots of estimates of room widthmade in feet and in metres.© 2010 by Taylor and Francis Group, LLC