Protected: Tidy the data up!9 January 2017 by Hasan Imtiaz 2 CommentsDifficulty level: 2.5/5 (1 votes) This content is password protected. To view it please enter your password below: Password: Please help us to improve R-exercises: Did you like this set? (1 star = no, not at all; 5 stars = yes, very much!) How difficult was this for you? (1 star=easy, 10 stars=hard) Are you a beginner (1 star), intermediate (2 stars) or advanced (3 stars) R user?