# NOTE: blip code must first be loaded into Splus for this function to work

#for grouped dot plot, x is numeric, y is factor or character
#second call superimposes vertical lines at medians

dot.plot <- function(x,y,xlab) {

blip(split(x,y),graph.type='c',box.p=NA,point.pattern='stacking',
        point.pch=1,point.cex=2,
        xlab=xlab)
par(new=T)
blip(split(x,y),graph.type='c',box.p=c(.499999,.500001),point.type='n',
        box.label.on=F)
}