- x contains the vars sex, heightsds and riskgroup
- rg contains a vars riskgroup, min (which is -inf in all cases) and max (which is inf in all cases); these define the backgroup colors for the different facets
p <- ggplot(x)
p +
geom_boxplot(aes(x=sex,y=heightsds,color=sex),fill="grey",notch=T,alpha=1) +
geom_rect(data=rg,aes(fill=riskgroup,xmin=min,ymin=min,xmax=max,ymax=max),alpha=0.15) +
facet_wrap(~riskgroup) +
scale_fill_manual(values=c("darkseagreen1","lightgreen","gold","firebrick")) +
ylab("Adult Height - Height SDS") + xlab("Sex") +
opts(panel.background=theme_rect(colour=NA),legend.position="none")
