Table 1.
Descriptive statistics for main variables.
| All participants |
|||
|---|---|---|---|
| Measure | Cronbach's α | Mean | SD |
| Morningness-Eveningness Questionnaire (5–27) | .67 | 13.81 | 3.68 |
| Mid-point sleep, school week (h:min) | N/A | 03:23 | 0:54 |
| Mid-point sleep, weekend (h:min) | N/A | 05:54 | 1:20 |
| Bedtime, school week (h:min) | N/A | 23:31 | 1:09 |
| Wake-up, school week (h:min) | N/A | 07:15 | 1:06 |
| Bedtime, weekend (h:min) | N/A | 01:09 | 1:26 |
| Wake-up, weekend (h:min) | N/A | 10:47 | 1:33 |
| Sleep length, school week (h:min) | N/A | 07:43 | 1:22 |
| Sleep length, weekend (h:min) | N/A | 09:46 | 1:23 |
| Subjective sleep need, school week, (h:min) | N/A | 08:11 | 1:17 |
| Subjective sleep need, weekend, (h:min) | N/A | 09:00 | 1:26 |
| Sleep deprivation, school week, N=310, (h:min) | N/A | –1:34 | 1:29 |
| Excessive sleep, school week, N=195, (h:min) | N/A | 1:11 | 1:08 |
| Sleep deprivation, weekend, N=139, (h:min) | N/A | –0:59 | 0:29 |
| Excessive sleep, weekend, N = 323, (h:min) | N/A | 1:50 | 1:10 |
| Tiredness, school week (2–10) | .67 | 6.47 | 1.58 |
| Tiredness, weekend (2–10) | .79 | 3.90 | 1.58 |
| Sleepiness, ESS (0–24) | .79 | 6.79 | 4.26 |
Abbreviations: N/A=not assessed, ESS=Epworth Sleepiness Scale.