TABLE 2.
Descriptive statistics for the predictors used in the Longitudinal analysis.
| Mean (min, max) | Vocabulary | Executive functions |
|---|---|---|
| Age Obs 2 (days) a | 824.60 (451, 1359) | 820.21 (451, 1359) |
| Age Obs 2 (months) a | 27 (14.7, 44.5) | 26.9 (14.7, 44.5) |
| SES | 0.04 (−2.55, 2.00) | 0.05 (−2.55, 2.00) |
| Sex (female/male) | 77/88 | 85/99 |
| Number of naps Obs 1 | 1.12 (0, 2) | 1.11 (0, 2) |
| Nap duration Obs 1 | 1.31 (0.00, 2.00) | 1.29 (0.00, 2.00) |
| Sleep efficiency Obs 1 | 0.96 (0.77, 1.00) | 0.96 (0.77, 1.00) |
| Time asleep night Obs 1 | 10.75 (5.16, 13.00) | 10.64 (5.16, 13.00) |
| Receptive vocabulary Obs 2 a | 349.34 (53, 416) | ‐ |
| Expressive vocabulary Obs 2 a | 273.37 (0, 416) | ‐ |
| CEF Obs 2 a | ‐ | 4.98 (2.71, 6.27) |
| Receptive vocabulary change rate b | 0.39 (0, 1.32) | ‐ |
| Expressive vocabulary change rate b | 0.55 (0, 1.87) | ‐ |
| CEF change rate b | ‐ | 0.0015 (−0.01, 01) |
| N | 165 | 184 |
Note: Because different samples were entered in the analysis for Vocabulary and Executive Functions, these are described separately.
a
Not entered in the model but provided for reference.
b
Units per day (e.g. words acquired per day, CEF score points acquired per day).