At Penn State, there are currently upwards of 40,000 undergraduate students. This does not mean that it is an easy school to get into, for the most part, most of the students I have seen have been fairly committed to their work, regardless of their college or focus of study. Of course, this does not mean that the average Penn State student is a super-focused studying machine. The students at Penn State are notorious for their love of partying. So, I'd say the average Penn State student is one who works hard during the day and parties hard at night. People who attend Penn State campus should be able to handle a good deal of stress and know when it's time to work, and when it's okay to go out and have some fun.
Of course, the type of person who attends Penn State should also be okay with not knowing most of the other people attending their university. With close to 40,000 students, it is beyond easy to become just another face in the crowd. Some student enjoy the anonymity. Other students find a way to stand out above the rest. Some decide to get involved in clubs and join small academic groups to lessen make their environment seem a little smaller. Others get involved in sports. Some work with things like student government. In short, if you're happy with a certain level of anonymity, Penn State would be a good fit. If you're not comfortable with that, it is possible to stand out, it just takes some effort.