Duke University is considered an elite university. Stanford is also considered a very elite university: perhaps top-3 and one of the very best. They are also both private, expensive universities. It would make sense that they are trying to out-do each other with expensive research leading to esoteric scientific findings.

University of Wisconsin is a public institution and is considered less elite. It is also often considered more of a "party school." So the joke is that they spent hardly any money at all on their study and that their research findings were more crude.

It's a basically a joke about elite vs. "common man" with the implied point being being that the common man approach is often more practical and correct (to humorous effect).