Type	n	%	Overall reading scale		Overall math scale		Overall science scale
Type	n	%	M^a	SD^b	M	SD	M	SD
7	165	4.3	471	46	482	55	473	50
6	533	13.5	410	45	400	58	409	50
5	900	22.8	355	43	344	59	350	51
4	1003	25.5	298	44	294	60	298	52
3	753	18.9	238	45	243	60	242	49
2	444	11.3	164	51	186	57	172	49
1	130	3.8	79	60	97	60	83	55