Section I questions get you a beta for 8/10 or more. Section II questions get a beta for 10/20 and an alpha for 15/20 or more. If I interpreted what my DoS was saying the other day correctly, class lists are drawn up according to raw mark. Then, people on the boundaries are promoted or demoted according to the number of alpha and betas they recieve (so, if you are initially in the 2i list but have lots and lots of alphas, you may get promoted to a first, whereas if you get a very high raw mark but not many alphas and are on the borderline, you will be demoted.)