On-line exam for my R course

Today was the day of the final exam for my R course in Paris Dauphine. In the previous years, the exam was an oral 20 minute interview with pairs of students about a project given to them at the beginning of the Fall semester. Unfortunately, this was taking forever since more than 150 students were registered for this course and it was not enough to discriminate between students who had really worked for that course and those who had bought the solution on the Internet.

So we decided to switch to an exam this year with the novelty that the exam would be on-line for students to test their answers on an R terminal and to cut and paste their answer inside a web form, the forms being saved and stored for the instructor to grade them later. The interface we used was WebCT, because this is the local standard, even though it is poorly adequate for a math or computer science exam, the HTML code being restricted and the forms missing facilities for storing computer code. This was a large scale experiment (with 172 students registered this year) and we had to split the exam into three consecutive sessions to face the shortage of available computers, meaning I had to stay in the computer room for 9 consecutive hours!, but the experiment worked in the sense that everyone got access to the exam form and no one lost his or her entry at the end of the exam. We use three slightly modified exams to avoid too much cheating. (The html version posted here is not the form used by the students.)

Now it remains to be seen whether or not the students got enough time to go over this fairly long questionnaire. From what I saw during the exams, students lost a lot of time checking elementary math questions by drawing plots, as for instance in the Accept-Reject question or even when finding the mode of the gamma distribution. A side question is to detect a possible bias in the grades of the last session, since they have had time to communicate with the students of the first session, even though we tried to collect the exam subjects at the end of the first session.