Oakland University joined 13 of Michigan\'s 15 public universities Monday by raising its tuition. On average, OU students will pay 7.97% more for tuition when they return this fall. Freshmen and sophomores will pay $6,637.50 a year; juniors and seniors, $7,275. Statewide, tuition increases have ranged from 4.8% at Northern Michigan University to 17.8% at Central Michigan University, which locked this year\'s tuition cost of $7,530 for Michigan residents for up to five years. Wayne State University\'s Board of Governors is expected to vote on a tuition hike Wednesday.