| Intervention | Control | Total | ||
---|---|---|---|---|---|
 | Low SEP | High SEP | Low SEP | High SEP | |
2015 | |||||
 n (% of total) | 726 (40.6%) | 244 (13.6%) | 635 (35.5%) | 185 (10.3%) | 1790 |
 Age mean (sd) | 9.7 (1.7) | 9.6 (1.7) | 9.8 (1.6) | 10.0 (1.6) | 9.7 (1.7) |
 Female (%) | 48.5% | 48.4% | 51.0% | 48.9% | 48.9% |
2019 | |||||
 n (% of total) | 456 (21.3%) | 422 (19.7%) | 708 (33.1%) | 551 (25.8%) | 2137 |
 Age mean (sd) | 9.8 (1.7) | 9.9 (1.7) | 9.8 (1.7) | 9.9 (1.7) | 9.9 (1.7) |
 Female (%) | 45.8% | 50.2% | 45.3% | 46.8% | 46.8% |