Read, “Usual scapegoats targeted over failing schools” online.

Whether a classroom of 25 or 50 students is appropriate depends on the level of the students. When we see college students in large lecture halls, we expect them to be autodidact. There are ways in large classrooms to adjust to this: for example, a teacher in a large classroom may create study groups and assign each of the students one part of an assignment. Each student must master his or her own content enough to be able to teach it to his or her group. The teacher then assesses all members of the group with content from each part. The success or failure of the whole depends on the proper working of each.

You are right, also, to raise concerns about small sample size. If exhaustive studies of funding versus performance have been done, I am not yet acquainted with them. While the idea does interest me, I am not sure how much research I will put into that per se since, at this time, I am more concerned with learning the classroom side of education than the administrative side.