Table 1. Participant Characteristics for Entire Sample.
| Mean | SD | Range | |
|---|---|---|---|
| Down Syndrome (N = 54) | |||
| Chronological Age (years) | 15.14 | 3.18 | 10.25 – 21.92 |
| Leiter-R (nonverbal IQ)* | 44.90 | 8.40 | 36 – 71 |
| Leiter-R (GSV) | 467.22 | 10.04 | 453 – 492 |
| PPVT-4 (GSV) | 142.59 | 23.35 | 89 – 190 |
|
| |||
| Intellectual Disability (N = 29) | |||
| Chronological Age (years) | 15.89 | 2.59 | 10.25 – 20.67 |
| Leiter-R (nonverbal IQ) | 52.54 | 10.84 | 36 – 77 |
| Leiter-R (GSV) | 475.45 | 9.16 | 458 – 487 |
| PPVT-4 (GSV) | 167.72 | 22.41 | 106 – 209 |
|
| |||
| Typically Developing (N = 35) | |||
| Chronological Age (years) | 6.99 | 2.56 | 4.08 – 13.50 |
| Leiter-R (nonverbal IQ) | 101.31 | 16.17 | 76 – 135 |
| Leiter-R (GSV) | 476.31 | 12.90 | 459 – 498 |
| PPVT-4 (GSV) | 152.97 | 18.12 | 126 – 198 |
Note. GSV = Growth Score Value.
*
Note. Mean and SD for Leiter-R (nonverbal IQ) for group with DS is based on a n of 52. The two participants who fell outside of the CA range of the Leiter-R were excluded from these analyses because the IQ score is calculated from age-based norms.