Variables (n) | PA | IR | SM | SA | HA | DB | Overall HL |
---|---|---|---|---|---|---|---|
Gender | |||||||
 Male (10990) | 15.89 ± 4.93 | 20.27 ± 3.97 | 21.18 ± 5.35 | 15.06 ± 3.72 | 14.65 ± 4.56 | 16.88 ± 4.25 | 103.94 ± 19.83 |
 Female (11638) | 15.04 ± 4.36 | 21.17 ± 3.47 | 21.17 ± 4.97 | 14.98 ± 3.54 | 15.27 ± 4.22 | 16.55 ± 3.40 | 104.17 ± 17.53 |
  t | 13.881 | −18.194 | 0.168 | 1.695 | −10.585 | 6.090 | − 0.936 |
  P-value | <  0.001 | <  0.001 | 0.860 | 0.090 | <  0.001 | <  0.001 | 0.349 |
Grade | |||||||
 Junior school (11993) | 16.11 ± 4.70 | 20.91 ± 3.72 | 21.79 ± 5.21 | 15.36 ± 3.62 | 15.16 ± 4.43 | 17.10 ± 4.23 | 106.45 ± 18.94 |
 Senior high school (10635) | 14.71 ± 4.52 | 20.53 ± 3.76 | 20.49 ± 5.01 | 14.63 ± 3.61 | 14.74 ± 4.35 | 16.27 ± 3.95 | 101.37 ± 18.01 |
  t | 22.844 | 7.678 | 19.206 | 15.180 | 7.182 | 15.210 | 20.598 |
  P-value | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 |
Registered residence | |||||||
 Rural (10882) | 15.08 ± 4.47 | 20.65 ± 3.71 | 20.85 ± 5.10 | 14.87 ± 3.61 | 14.74 ± 4.33 | 16.19 ± 4.10 | 102.38 ± 18.15 |
 Urban (11746) | 15.80 ± 4.81 | 20.81 ± 3.78 | 21.48 ± 5.20 | 15.16 ± 3.65 | 15.17 ± 4.45 | 17.19 ± 4.10 | 105.62 ± 19.03 |
  t | −11.738 | −3.386 | −9.232 | −5.967 | − 7.373 | − 18.209 | −13.081 |
  P-value | <  0.001 | 0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 |
Boarding on school days | |||||||
 Yes (11320) | 14.84 ± 4.39 | 20.63 ± 3.66 | 20.69 ± 5.00 | 14.83 ± 3.55 | 14.71 ± 4.32 | 16.21 ± 4.00 | 101.90 ± 17.81 |
 No (11308) | 16.07 ± 4.84 | 20.84 ± 3.83 | 21.67 ± 5.27 | 15.22 ± 3.70 | 15.22 ± 4.46 | 17.21 ± 4.18 | 106.23 ± 19.27 |
  t | −20.070 | −4.202 | −14.231 | − 8.091 | − 8.853 | − 18.417 | − 17.530 |
  P-value | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 |
Household structure | |||||||
 Only child (9720) | 15.60 ± 4.79 | 20.72 ± 3.89 | 21.31 ± 5.23 | 15.03 ± 3.69 | 15.06 ± 4.58 | 17.11 ± 4.15 | 104.81 ± 19.20 |
 More than one child (12908) | 15.34 ± 4.57 | 20.75 ± 3.63 | 21.08 ± 5.10 | 15.02 ± 3.59 | 14.90 ± 4.35 | 16.41 ± 4.09 | 103.49 ± 18.26 |
  t | 4.131 | − 0.596 | 3.332 | 0.141 | 2.658 | 12.624 | 5.266 |
  P-value | <  0.001 | 0.551 | 0.001 | 0.888 | 0.008 | <  0.001 | <  0.001 |
Father’s educational level | |||||||
  < High school degree (13006) | 14.99 ± 4.41 | 20.59 ± 3.71 | 20.83 ± 5.08 | 14.80 ± 3.61 | 14.70 ± 4.31 | 16.29 ± 4.06 | 102.20 ± 18.05 |
  ≥ High school degree (9424) | 16.10 ± 4.90 | 20.96 ± 3.75 | 21.68 ± 5.20 | 15.34 ± 3.61 | 15.35 ± 4.48 | 17.30 ± 4.11 | 106.73 ± 19.01 |
 No father (198) | – | – | – | – | – | – | – |
  t | −17.695 | −7.321 | − 12.180 | − 11.022 | − 11.079 | − 18.256 | − 18.116 |
  P-value | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 |
Mother’s educational level | |||||||
  < High school degree (14335) | 14.98 ± 4.41 | 20.58 ± 3.68 | 20.85 ± 5.06 | 14.80 ± 3.60 | 14.68 ± 4.31 | 16.34 ± 4.07 | 102.24 ± 17.94 |
  ≥ High school degree (8105) | 16.30 ± 4.96 | 21.04 ± 3.79 | 21.79 ± 5.24 | 15.42 ± 3.63 | 15.48 ± 4.50 | 17.39 ± 4.12 | 107.42 ± 19.27 |
 No mother (188) | – | – | – | – | – | – | – |
  t | −20.544 | −8.805 | − 13.270 | −12.247 | − 13.147 | − 18.568 | − 20.244 |
  P-value | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 |
Self-reported family economy | |||||||
 Bad (3240) | 14.78 ± 4.69 | 19.52 ± 4.32 | 19.70 ± 5.40 | 14.08 ± 3.96 | 14.30 ± 4.53 | 15.79 ± 4.30 | 98.17 ± 19.99 |
 General (16345) | 15.35 ± 4.52 | 20.87 ± 3.55 | 21.26 ± 5.01 | 15.06 ± 3.52 | 14.97 ± 4.31 | 16.71 ± 4.02 | 104.23 ± 17.83 |
 Good (3043) | 16.70 ± 5.19 | 21.30 ± 3.82 | 22.33 ± 5.31 | 15.80 ± 3.64 | 15.63 ± 4.60 | 17.66 ± 4.28 | 109.43 ± 19.90 |
  F | 147.758 | 218.954 | 216.155 | 182.200 | 72.745 | 163.181 | 294.662 |
  P-value a | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 |
Support from friends | |||||||
 None (599) | 14.13 ± 5.77 | 16.21 ± 5.54 | 18.13 ± 6.37 | 12.66 ± 4.72 | 13.87 ± 5.06 | 15.06 ± 5.11 | 90.05 ± 20.01 |
 Few (14535) | 14.94 ± 4.37 | 20.37 ± 3.64 | 20.67 ± 5.02 | 14.66 ± 3.56 | 14.77 ± 4.31 | 16.45 ± 4.01 | 101.86 ± 17.74 |
 Lot (7494) | 16.56 ± 4.92 | 21.79 ± 3.35 | 22.42 ± 5.05 | 15.92 ± 3.46 | 15.43 ± 4.48 | 17.34 ± 4.18 | 109.45 ± 18.43 |
  F | 331.936 | 867.191 | 406.191 | 447.278 | 74.106 | 165.928 | 613.364 |
  P-value a | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 | <  0.001 |