Table I.
Descriptive Statistics for Measures of Intellectual Abilities, Vocabulary Abilities, and Adaptive Behavior
| Measure | Time 1 | Time 2 | Difference | |Difference| | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean | SD | Range | Mean | SD | Range | Mean | SD | Range | Mean | SD | Range | |
| DAS-II GCA | 68.88 | 11.01 | 44 – 98 | 68.03 | 12.22 | 38 – 96 | −0.86 | 6.98 | −19 – 14 | 5.67 | 4.11 | 0 – 19 |
| DAS-II Verbal SS | 79.97 | 14.99 | 31 – 112 | 76.86 | 15.83 | 31–106 | −3.12 | 10.61 | −34 – 21 | 8.25 | 7.31 | 0 – 34 |
| DAS-II Nonverbal Reasoning SS | 84.38 | 11.90 | 59 – 111 | 79.93 | 12.77 | 46 –107 | −4.45 | 9.47 | −28 – 16 | 8.37 | 6.22 | 0 – 28 |
| DAS-II Spatial SS | 56.26 | 11.78 | 32 – 91 | 58.68 | 13.20 | 32 – 86 | 2.42 | 10.02 | −26 – 26 | 7.50 | 7.02 | 0 – 26 |
| DAS-II SNC | 66.30 | 11.17 | 39 – 90 | 65.82 | 13.09 | 39 – 93 | −0.49 | 8.41 | −16 – 21 | 6.83 | 4.87 | 0 – 21 |
| PPVT-4 SS | 89.18 | 14.02 | 47 – 120 | 86.59 | 14.62 | 41 – 115 | −2.59 | 8.31 | −19 – 17 | 6.72 | 5.49 | 0 – 19 |
| EVT-2 SS | 85.08 | 13.71 | 46 – 112 | 82.74 | 12.48 | 49 – 113 | −2.34 | 7.53 | −22 – 22 | 5.92 | 5.17 | 0 – 22 |
| SIB-R Broad Independence | 55.51 | 17.13 | 16 – 92 | 49.37 | 18.11 | 0 – 95 | −6.14 | 10.12 | −40 – 20 | 8.99 | 7.67 | 0 – 40 |
| SIB-R Motor Skills | 60.05 | 16.45 | 26 – 96 | 54.21 | 15.24 | 21 – 96 | −5.84 | 10.97 | −45 – 20 | 9.50 | 7.97 | 0 – 45 |
|
SIB-R Social Interaction & Communication Skills |
73.12 | 13.96 | 43 – 104 | 71.26 | 15.19 | 30 – 106 | −1.86 | 10.01 | −30 – 28 | 7.49 | 6.85 | 0 – 30 |
| SIB-R Personal Living Skills | 57.07 | 15.39 | 18 – 88 | 58.76 | 14.93 | 25 – 98 | 1.70 | 9.67 | −21 – 29 | 7.41 | 6.39 | 0 – 29 |
| SIB-R Community Living Skills | 58.36 | 17.89 | 20 – 87 | 48.47 | 19.04 | 4 – 90 | −9.88 | 14.25 | −51 – 26 | 13.30 | 11.08 | 1 – 51 |
Note. Difference = Time 2 SS – Time 1 SS. |Difference| = Absolute value of the difference between Time 2 and Time 1 SSs.
Abbreviations: DAS-II (Differential Ability Scales-II), General Conceptual Ability (GCA; similar to IQ), SS (standard score), SNC (Special Nonverbal Composite; similar to Performance IQ), PPVT-4 (Peabody Picture Vocabulary Test-4), EVT-2 (Expressive Vocabulary Test-2), SIB-R (Scales of Independent Behavior-Revised)