Table 4. Study sample.
| Afternoon group n = 25 | Evening group n = 25 | F | P | |
| Age in years | 16.7±0.5 | 16.5±0.5 | 1.3 | 0.257 |
| IQ (SPM) | 103.4±9.3 | 104.1±9.1 | 0.1 | 0.807 |
| BDI | 3.3±3.1 | 3.6±3.3 | 1.3 | 0.720 |
| PSQ-20 | 28.2±13.8 | 23.3±13.5 | 1.6 | 0.215 |
| SELLMO – Achievement motivation | 55.2±13.4 | 57.8±9.1 | 0.6 | 0.425 |
| PSQI – Total score | 3.4±1.3 | 3.0±1.6 | 1.0 | 0.332 |
| PSQI – Habitual sleep time | 7.9±0.6 | 8.0±0.7 | 0.1 | 0.705 |
| SF-A sleep quality | 3.9±0.6 | 4.0±0.5 | 0.2 | 0.663 |
| ESS | 6.2±2.8 | 6.7±2.9 | 0.4 | 0.534 |
| TAP visual alertness (ms) | 256.7±26.9 | 243.9±27.7 | 2.6 | 0.111 |
| TAP auditory alertness (ms) | 260.7±28.3 | 248.0±30.0 | 2.3 | 0.140 |
| Working memory (digit span test) | 16.2±3.1 | 16.5±3.0 | 0.1 | 0.746 |
Values represent means ± SD. IQ, Intelligence quotient; SPM, Standard Progressive Matrices; BDI, Beck Depression Inventory; PSQ-20, Perceived Stress Questionnaire 20 item version; SELLMO, Scales to Asses Goal Orientation and Achievement Motivation; PSQI, Pittsburgh Sleep Quality Index; SF-A, Sleep Questionnaire A; ESS, Epworth Sleepiness Scale; TAP, Testbattery for the Assessment of Attention.