Table 2.
Descriptive statistics and reliability estimates for each of the WM accuracy rate measures.
| Variable | M (SD) | Skewness BT | Kurtosis BT | Skewness AT | Kurtosis AT | α |
|---|---|---|---|---|---|---|
| Numerical-verbal | ||||||
| SSTF | 73.19 (17.06) | -0.79 | 1.23 | 0.01 | -0.56 | 0.66 |
| SSTB | 62.93 (18.66) | -0.18 | -0.17 | 0.00 | -0.42 | 0.71 |
| CST | 70.96 (29.01) | -0.99 | -0.10 | 0.00 | -1.43 | 0.83 |
| RMT | 70.49 (21.32) | -0.94 | 0.79 | -0.01 | -0.78 | 0.72 |
| 2-back | 57.68 (26.37) | -0.82 | 0.43 | -0.00 | -0.82 | 0.98 |
| Visuospatial | ||||||
| SSTF | 62.06 (18.37) | -0.36 | 0.20 | 0.05 | -0.27 | 0.71 |
| SSTB | 64.66 (20.13) | -0.91 | 0.82 | -0.02 | -0.46 | 0.79 |
| CST | 42.15 (30.34) | 0.37 | -0.96 | 0.03 | -1.02 | 0.85 |
| RMT | 54.15 (24.35) | -0.33 | -0.67 | 0.02 | -0.77 | 0.77 |
| 2-back | 53.04 (30.23) | -0.66 | -0.04 | 0.01 | -0.94 | 0.98 |
SSTF, simple span task forward; SSTB, simple span task backward; CST, complex span task; RMT, running memory task; BT, before Box-Cox transformation; AT, after Box-Cox transformation; α, Cronbach’s alpha. Test scores are provided in percent correct, except for the 2-back tasks, where we employed the corrected recognition score, i.e., percent hits minus percent false alarms. n = 656.