Table 4.
Descriptive statistics for variables included in the regression analyses.
| Variable | Mean | Median | SD | Interquartile range | Range |
|---|---|---|---|---|---|
| Independent | |||||
| CDI-EV at 24 months | 43.21 | 22.00 | 41.89 | 4.00–41.00 | 0–176 |
| CA (in months) at onset of declarative pointing | 29.27 | 24.08 | 13.60 | 20.40–31.87 | 14.55–63.54 |
| Dependent | |||||
| CDI-EV at 48 months | 388.72 | 423.00 | 220.93 | 196.00–569.00 | 4–679 |
| CDI-SC at 48 months | 14.91 | 9.00 | 14.44 | 0–31.00 | 0–37a |
| PPVT-4 SS at 48 months | 80.08 | 89.00 | 24.50 | 65.50–97.00 | 20b–113 |
| EVT-2 SS at 48 months | 79.62 | 83.00 | 23.32 | 71.50–97.00 | 25c–111 |
| MSEL-ELC at 48 months | 63.40 | 61.00 | 13.60 | 50.00–75.00 | 49b–96 |
CDI-EV, MacArthur-Bates Communicative Development Inventory: Words and Sentences expressive vocabulary size; CA, chronological age; CDI-SC, MacArthur-Bates Communicative Development Inventory: Words and Sentences sentence complexity score; PPVT-4, Peabody Picture Vocabulary Test-4; EVT-2, Expressive Vocabulary Test-2; MSEL-ELC, Mullen Scales of Early Learning Early Learning Composite; SS, standard score.
N = 47 for all measures except for PPVT-4 SS and EVT-2 SS, for which N = 37.
a
highest possible CDI-SC;
b
lowest possible SS;
c
lowest possible SS for 48-month-olds.