Another thing to think about would be the ratio of students enrolled in a school or a given class. Are there more females than males? Also, from a forensic and psychological standpoint does seating have anything to do with it? I seem to remember a study some years ago (and with my old mind I can't count on accuracy) that talked about girls often sitting closer to the front in classrooms. That would certainly impact the ratio if someone enters a room whose door is located near the front of class and opens fire.
Just a thought.
