p1 <- hist(epfl$position, plot = FALSE, breaks = 0:3)
p1$counts=p1$counts/sum(p1$counts)
p2 <- hist(uas$position, plot = FALSE, breaks = 0:3)
p2$counts=p2$counts/sum(p2$counts)
plot( p1, col=rgb(1,0,0,0.5), main = "Position distribution histogram", xlab = "Position {student, employee, executive}")
plot( p2, col=rgb(0,0,1,0.5), add=T)
legend("topright", legend=c("EPFL","UAS"), col=c(rgb(1,0,0,0.5), rgb(0,0,1,0.5)), pt.cex=2, pch=15)