This is what you should be doing: plot(density(Annie), col="red") lines(density(Brian), col="blue") lines(density(Chris), col="green") lines(density(Zo

This is what you should be doing: plot(density(Annie), col="red") lines(density(Brian), col="blue") lines(density(Chris), col="green") lines(density(Zoe), col="cyan") This is the plot you get: http://i.imgur.com/sY2awX7.png http://i.imgur.com/sY2awX7.png