Table 1.
Demographic characteristics of study participants.
| Total | |||
|---|---|---|---|
| n | % | ||
| Total | 100.0 | ||
| Sex | 27,954 | ||
| Boy | 14,892 | 53.3 | |
| Girl | 13,062 | 46.7 | |
| Grade | |||
| 5th | 14,026 | 50.2 | |
| 6th | 13,928 | 49.8 | |
| Academic performance (Chinese) | |||
| A | 12,968 | 46.4 | |
| B | 10,753 | 38.5 | |
| C | 3479 | 12.4 | |
| D | 754 | 2.7 | |
| Academic performance (Math) | |||
| A | 13,502 | 48.3 | |
| B | 8577 | 30.7 | |
| C | 4162 | 14.9 | |
| D | 1713 | 6.1 | |
| Academic performance (English) | |||
| A | 12,683 | 45.4 | |
| B | 8854 | 31.7 | |
| C | 4610 | 16.5 | |
| D | 1807 | 6.5 | |
| Siblings | |||
| Yes | 6518 | 23.3 | |
| No | 21,436 | 76.7 | |
| Father Education Level | |||
| Middle school or below | 6131 | 21.9 | |
| High school | 6948 | 24.9 | |
| Undergraduate | 10,557 | 37.8 | |
| Graduate | 1232 | 4.4 | |
| Unknown | 3086 | 11.0 | |
| Mother Education Level | |||
| Middle school or below | 7143 | 25.6 | |
| High school | 7070 | 25.3 | |
| Undergraduate | 10,039 | 35.9 | |
| Graduate | 790 | 2.8 | |
| Unknown | 2912 | 10.4 | |
| Socioeconomic status | |||
| Low | 5386 | 19.3 | |
| Middle | 20,708 | 74.1 | |
| High | 1860 | 6.7 | |
| Sports participation | |||
| Never | 12,233 | 43.8 | |
| 1–3 times a month | 6112 | 21.9 | |
| 1–2 times a week | 5347 | 19.1 | |
| 3 or more times a week | 4262 | 15.2 | |
| Means | SD | ||
| Age | 11.5 | 0.8 | |