A college prep program compared the practice SAT math scores given before and after a seven-week instruction for each student. The scores are given below. Student 1 2 3 4 5 6 7 8 9 Before 750 800 500 520 490 670 600 410 440 After 780 800 550 550 570 690 700 440 480 Test if the average score has been raised by more than 30 points and find the -value (round off to second decimal place). Assume normal population.