| Variable | Frequency (N = 418) | Mean | SD* | Statistics | p-value |
| Age (months) |
|
|
|
|
|
| 6 to 11 | 96 | 0.9 | ±0.7 | F(ANOVA) = 9.508 | <0.001* |
| 12 to 23 | 116 | 0.8 | ±0.7 |
|
|
| 24 to 35 | 98 | 1.3 | ±1.0 |
|
|
| 36 to 47 | 51 | 1.0 | ±1.0 |
|
|
| 48 to 60 | 57 | 1.4 | ±1.0 |
|
|
| Sex |
|
|
|
|
|
| Male | 219 | 1.1 | ±0.9 | Student t-test (t = 0.686) | 0.493 |
| Female | 199 | 0.9 | ±0.8 |
|
|
| Total | N = 418 | 1.0 | ±0.9 |
|
|