Preface to First Edition - lib

36 DATA ANALYSIS USING GRAPHICAL DISPLAYSR> plot(R_happy ~ R_health, data = CHFLS)R_happyVery unhappy Not too happy Somewhat happy Very happyPoor Fair Good Excellent0.0 0.2 0.4 0.6 0.8 1.0R_healthFigure 2.7Spineplot of health status and happiness.R> xtabs(~ R_happy + R_health, data = CHFLS)R_healthR_happy Poor Not good Fair Good ExcellentVery unhappy 2 7 4 1 0Not too happy 4 46 67 42 26Somewhat happy 3 77 350 459 166Very happy 1 9 40 80 150A spineplot is a group of rectangles, each representing one cell in the twowaycontingency table. The area of the rectangle is proportional with thenumber of observations in the cell. Here, we produce a mosaic plot of healthstatus and happiness in Figure 2.7.Consider the right upper cell in Figure 2.7, i.e., the 150 very happy womenwith excellent health status. The width of the right-most bar corresponds tothe frequency of women with excellent health status. The length of the top-© 2010 by Taylor and Francis Group, LLC