Table 4.
Demographic information for participants by treatment condition.
| Characteristic | Higher dose number condition | Lower dose number condition |
|---|---|---|
| n | 15 (six females, nine males) | 9 (five females, four males) |
| Age in months, M (SD) | 30.87 (5.52) | 29.67 (4.79) |
| Standard score on the Bayley, a M (SD) | 93.21 (6.96) | 97.22 (11.75) |
| Number of words produced on the initial MCDI, b M (SD) | 71.6 (139.45) | 68.33 (93.32) |
| Number of words understood on the initial MCDI, M (SD) | 343.8 (146.48) | 341.44 (131.36) |
| Race | 11 White, 3 more than one race, 1 Black/African American | 7 White, 2 more than one race |
| Ethnicity | 8 Hispanic, 7 non-Hispanic | 3 Hispanic, 6 non-Hispanic |
| Maternal education | ||
| High school | 1 | |
| Associate degree or some college | 6 | 3 |
| Bachelor's degree | 2 | 3 |
| Graduate degree | 6 | 3 |
Note. Bayley = Bayley Scales of Infant and Toddler Development–Third Edition (Bayley, 2006); MCDI = MacArthur–Bates Communicative Development Inventories: Words and Sentences (Fenson et al., 2007).
Data are available for the Bayley for 23 participants. One participant in the higher dose number condition was outside the age range for this measure, and that participant's nonverbal intelligence was measured using the Kaufman Assessment Battery for Children–Second Edition (Kaufman & Kaufman, 2004). That child's standard score was 93. Testing for one child in each condition was stopped before reaching a ceiling, likely underestimating those children's actual abilities.
All participants but one fell below the 5th percentile based on the number of words produced for their age/sex on the MCDI. One participant's score was at the 5th percentile.