+# generate the scaled proportion graph
+filename.prop <- paste(y,"-proportion.png",sep="")
+
+max.value <- tapply(d$plot.weight, d$day.of.week, sum)[1]
+png(filename.prop, width=8,height=6, unit="in", res=200)
+p <- qplot(day.of.week, data=d, fill=as.factor(rating), geom="bar",
+ weight=plot.weight, main=y)
+p <- p + scale_x_discrete("Day of Week") +
+ scale_y_continuous("percentage of reviews",
+ breaks=(0:4 * max.value/4), labels=seq(0,100, 25)) +
+ scale_fill_discrete("", breaks=as.character(rev(1:5)))
+print(p)
+dev.off()
+
+