Table II.
Descriptive Statistics
| Task | N | M | SD | Range | Skewness | Kurtosis |
|---|---|---|---|---|---|---|
| Wave 1 (age 56) | ||||||
| Letter F | 1277 | 12.28 | 4.09 | 1 – 29 | 0.29 | −0.02 |
| Letter A | 1277 | 11.15 | 3.90 | 1 – 29 | 0.41 | 0.34 |
| Letter S | 1277 | 13.48 | 4.32 | 1 – 31 | 0.25 | 0.08 |
| Animals | 1275 | 19.20 | 4.43 | 6 – 39 | 0.26 | 0.26 |
| Boys’ Names | 1276 | 19.09 | 4.48 | 6 – 40 | 0.34 | 0.58 |
| Fruits/Furniture | 1277 | 12.75 | 2.55 | 4 – 22 | −0.01 | 0.30 |
| Wave 2 (Age 62) | ||||||
| Letter F | 1189 | 11.68 | 4.04 | 0.82 – 28.00 | 0.32 | 0.14 |
| Letter A | 1189 | 10.39 | 3.87 | 1.44 – 26.00 | 0.31 | −0.06 |
| Letter S | 1189 | 12.70 | 4.31 | 0.00 – 28.83 | 0.24 | −0.08 |
| Animals | 1189 | 19.11 | 4.51 | 5.08 – 35.08 | 0.17 | 0.11 |
| Boys’ Names | 1189 | 18.32 | 4.50 | 4.31 – 37.31 | 0.23 | 0.47 |
| Fruits/Furniture | 1188 | 12.30 | 2.58 | 2.71 – 21.71 | 0.02 | 0.38 |
Note: In all analyses, these dependent measures were standardized residual scores after removing the effect of age on each measure, but the unadjusted scores are presented here. However, the wave 2 scores reported here reflect the adjustments for practice effects for individuals who participated at both waves of assessment.