Table 2.
Descriptive statistics results for confounding variables and baseline measures.
| 2700 K | 6500 K | Statistics | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 100 lx | 1000 lx | 100 lx | 1000 lx | CCT | Illuminance | CCT*illuminance | R2 | |||||||
| EMM (SE) | EMM (SE) | EMM (SE) | EMM (SE) | F | df | p | F | df | p | F | df | p | ||
| Sleep duration | 7.67 (0.19) | 7.62 (0.19) | 7.98 (0.19) | 8.37 (0.19) | 5.81 | (1,48) | 0.02 | 1.12 | (1,48) | 0.30 | 1.86 | (1,48) | 0.18 | 0.05 |
| Sleep quality | 1.54 (0.54) | 2.79 (0.54) | 2.50 (0.54) | 2.96 (0.54) | 0.87 | (1,48) | 0.36 | 3.26 | (1,48) | 0.08 | 0.70 | (1,48) | 0.41 | 0.10 |
| Light sensitivity | 7.67 (0.40) | 7.13 (0.40) | 7.75 (0.40) | 7.38 (0.40) | 0.10 | (1,48) | 0.76 | 6.08 | (1,48) | 0.02 | 0.20 | (1,48) | 0.66 | − 0.10 |
| Sleepiness (KSS) | 2.96 (0.25) | 2.88 (0.25) | 3.17 (0.25) | 2.83 (0.25) | 0.08 | (1,48) | 0.78 | 1.45 | (1,48) | 0.24 | 0.52 | (1,48) | 0.47 | 0.05 |
| Happy | 3.67 (0.14) | 3.63 (0.14) | 3.63 (0.14) | 3.71 (0.14) | 0.02 | (1,48) | 0.90 | 0.30 | (1,48) | 0.90 | 0.27 | (1,48) | 0.60 | 0.01 |
| Sad | 2.00 (0.17) | 1.71 (0.17) | 1.83 (0.17) | 1.67 (0.17) | 0.26 | (1,48) | 0.61 | 2.73 | (1,48) | 0.11 | 0.20 | (1,48) | 0.65 | 0.05 |
EMM estimated marginal means, SE standard errors.
A significant difference is indicated by bold labels.
Effect sizes (pseudo R2-values (R2pseudo)) indicates the proportion (percentage) of the reduction in the variance of residuals from the null model to the final (full) model at level two; it is worth mentioning that this measure can also have negative values71.