You seem to have answered your own question by observing that our internet connection gets a lot snappier when lots of students go home. You should try it over the summer.
Seriously though, all those little laptops sitting around downloading and uploading files take up a lot of bandwidth. Lots of P2P apps turn your computer into a server as well as a client (unless we prevent that?).
Perhaps Chris or Mike or somebody with the knowledge could post a typical day's bandwidth profile, or even a week's.
And I don't know whether this is a factor, but I wouldn't be surprised if local traffic didn't cause a lag for you in the dorms. Get a few people playing an on-line game and your local router may be awfully busy. Some schools even have separate lines for students and non-students because of this.
Oh, and Chris wrote:
due to reading days, people are so engrossed in their studies
which is very funny.
Glad to see that he hasn't lost his sense of humor since graduating.