Table 8.
Percentage, valid N, and T-tests of early childhood developmental milestones.
| Developmental milestone | SPD % (N) | ASD (%) (N) | t (p) |
|---|---|---|---|
| Not rolling over by 6 months | 11.4 (429) | 13.6 (337) | −0.928 (0.354) |
| Not walking by 18 months | 6.1 (590) | 7.7 (415) | −1.000 (0.318) |
| Not saying words by 12 months | 33.3 (519) | 55.4 (345) | −6.574 (<0.001) |
| Not sitting alone by 10 months | 2.9 (509) | 6.5 (369) | −2.573 (0.010) |
| Not saying sentences by 24 months | 20.8 (452) | 55.8 (251) | −10.075 (<0.001) |
| Not crawling by 12 months | 6.0 (453) | 9.3 (333) | −1.776 (0.076) |
| Brief crawling phase | 29.1 (560) | 36.9 (347) | −2.445 (0.015) |
| Absent crawling phase | 8.0 (552) | 10.0 (411) | −2.410 (0.016) |
| Demonstrating hesitancy on stairs | 28.3 (573) | 40.1 (399) | −3.880 (<0.001) |