Table 1. Socio-demographic characteristics of females from one-child families and those students with siblings.
| Characteristics | Total (n = 4769) | Only-child | |||
| Yes(n = 1954) | No(n = 2815) | χ2 | P | ||
| Current age | 20.034 | <0.001 | |||
| ≤18 | 458(9.6) | 210(10.7) | 248(8.8) | ||
| 19–21 | 3143(65.9) | 1328(68.0) | 1815(64.5) | ||
| ≥22 | 1168(24.5) | 416(21.3) | 752(26.7) | ||
| Mean ± SD | 20.4±1.5 | 20.3±1.4 | 20.4±1.5 | ||
| Major | 400.542 | <0.001 | |||
| Literature and history | 1862(39.0) | 776(39.7) | 1086(38.6) | ||
| Science and technology | 1167(24.5) | 323(16.5) | 844(30.0) | ||
| Medical science | 985(20.7) | 317(16.2) | 668(23.7) | ||
| Art | 755(15.8) | 538(27.5) | 217(7.7) | ||
| Grade | 52.507 | <0.001 | |||
| Freshmen | 1373(28.8) | 492(25.2) | 881(31.3) | ||
| Sophomores | 1195(25.1) | 446(22.8) | 749(26.6) | ||
| Juniors | 1309(27.4) | 633(32.4) | 676(24.0) | ||
| Seniors | 892(18.7) | 383(19.6) | 509(18.1) | ||
| Nationality | 21.290 | <0.001 | |||
| Han | 4217(88.4) | 1778(91.0) | 2439(86.6) | ||
| minority | 552(11.6) | 176(9.0) | 376(13.4) | ||
| Home location | |||||
| Eastern coastal regions | 561(11.8) | 221(11.3) | 340(12.1) | ||
| Central areas | 3548(74.4) | 1518(77.7) | 2030(72.1) | ||
| Western areas | 660(13.8) | 215(11.0) | 445(15.8) | ||
| Address in your middle school | 1363.760 | <0.001 | |||
| Province capital city | 1831(38.4) | 1331(68.1) | 500(17.8) | ||
| County capital city | 2101(44.1) | 583(29.8) | 1518(53.9) | ||
| Countryside | 837(17.5) | 40(2.0) | 797(28.3) | ||
| Parents' economic status | 317.018 | <0.001 | |||
| Poor | 855(17.9) | 155(7.9) | 700(24.9) | ||
| Average | 3249(68.1) | 1382(70.7) | 1867(66.3) | ||
| Rich | 665(13.9) | 417(21.3) | 248(8.8) | ||