That is interesting. So Luo, do you have 15 student teams spread through 12 events at Regionals or fewer students/team at Invites?
There's also a great % differential of teams advancing to State and my state allows multiple teams/school at State. So some MN schools may send more teams to allow more students to participate since many won't get the chance to compete at State.
As you probably gleaned from haverstall's post, we send four full 15-person teams to regionals to compete in the 12 events. Thus, regionals is a sort of "easy" competition in which each student does only 1-2 events. It is my understanding that teams with enough people to fill 15-person teams tend to do so at regionals, opting to have their students participate in fewer events each.
Proud alumnus of Mounds View High School Science Olympiad, Arden Hills, MN
Co-founder of the MIT Science Olympiad Invitational Tournament: http://scioly.mit.edu/