Table 1 The demographic characteristics of the LBC and NLBC groups
Variables | Total (n = 16,866) | NLBC (n = 10,770) | LBC (n = 6,096) | χ2 | p |
|---|---|---|---|---|---|
Gender : N (%) | |||||
 Boy | 8,850(52.5) | 5,629(52.3) | 3,221(52.8) | 0.512 | 0.480 |
 Girl | 8,016(47.5) | 5,141(47.7) | 2,875(47.2) |  |  |
Learning stage : N (%) | |||||
 Primary school | 8,222(48.7) | 5,690(52.8) | 2,532(41.5) | 460.163 | 0.000 |
 Junior middle school | 6,051(35.9) | 3,887(36.1) | 2,164(35.5) |  |  |
 Senior middle school | 2,593(15.4) | 1,193(11.1) | 1,400(23.0) |  |  |
Residence : N (%) | |||||
 County town | 9,893(58.7) | 7,374(68.5) | 2,519(41.3) | 1.181 | 0.000 |
 Rural area | 6,973(41.3) | 3,396(31.5) | 3,577(58.7) |  |  |
Boarder : N (%) | |||||
 No | 14,047(83.3) | 9,702(90.1) | 4,345(71.3) | 9.894 | 0.000 |
 Yes | 2,819(16.7) | 1,068(9.9) | 1,751(28.7) |  |  |
Only child : N (%) | |||||
 No | 14,498(86.0) | 9,380(87.1) | 5,118(84.0) | 31.741 | 0.000 |
 Yes | 2,368(14.0) | 1,390(12.9) | 978(16.0) |  |  |
Family structure types : N (%) | |||||
 Nuclear families | 14,701(87.2) | 9,861(91.6) | 4,840(79.4) | 531.532 | 0.000 |
 Single-parent families | 1,342(8.0) | 519(4.8) | 823(13.5) |  |  |
 Remarried families | 823(4.8) | 390(3.6) | 433(7.1) |  |  |