plot.new()
plot(density(Groups[F1 == "A"], adjust = 1.5), xlim = c(0, 20), col = "blue", 
     main = "Variation between & within groups", xlab = "Numerical variable value")            
points(density(Groups[F1 == "B"], adjust = 1.5), type = "l", col = "yellow")
points(density(Groups[F1 == "C"], adjust = 1.5), type = "l", col = "red")
text(5, 0.02, "A", col = "blue")
text(10, 0.02, "B", col = "yellow")
text(15, 0.02, "C", col = "red")
arrows(3.3, 0.1, 6.8, 0.1, col = "blue", code = 3)
arrows(8.3, 0.1, 11.8, 0.1, col = "yellow", code = 3)
arrows(13.3, 0.1, 16.8, 0.1, col = "red", code = 3)
arrows(5, 0.15, 10, 0.15, col = "green", code = 3)
arrows(10, 0.2, 15, 0.2, col = "orange", code = 3)
arrows(5, 0.25, 15, 0.25, col = "purple", code = 3)