Grade (Time1)

n

male

female

Grade (Time 2)

n

male

female

Cohort 1

5

395

194

201

6

354

170

184

Cohort 2

6

399

180

219

7

220

89

131

Cohort 3

7

401

180

221

8

366

161

205

Cohort 4

8

324

186

138

9

298

170

128

Total Independent N

1519

1238