That is what recruitment is for.
If you're looking for stereotypes, A) we don't know where you go to school, B) most GCers know that posting stereotypes is in poor taste, and C) there aren't "National" stereotypes because every NPC has strong and weak chapters.
ETA: If you want to know about the sororities on a(n) (inter)national level,
Alpha Delta Pi
Delta Zeta
Zeta Tau Alpha
Most women who join NPC chapters typically choose the chapter at their school that is the best fit, although it is common to take the (inter)national organization's values and history into consideration.
Also, just a guess, but I think you have more chapters at your school than those 3, so you should really keep your options open.
Hybrid Mode
