here is the presentation for this week and here is a heavily commented R script.
the 3rd R session is over. Have a look at the slides and the solution code if you want.
Feel free to drop me an email with all your questions at email@example.com
here are the slides for the R session on ggplot2.
Just in case you want to view the slides of the first introductory R session again you can download them here or the R code here (Data)