Table 1 Sample characteristics of the four measurement points
Measurement point | 1. Measurement | 2. Measurement | 3. Measurement | 4. Measurement |
|---|---|---|---|---|
t1 | t2 | t3 | t4 | |
Duration | November/December 2012 | January/February 2014 | January/February 2015 | April/May 2015 |
Total na | 1.757 | 1.585 | 1.482 | 1.367 |
Valid nb | 1.671 | 1.454 | 1.324 | 1.167 |
| Â | n | % | n | % | n | % | n | % |
|---|---|---|---|---|---|---|---|---|
Sex | ||||||||
 Male | 615 | 36.8 | 536 | 36.9 | 483 | 36.5 | 406 | 34.8 |
 Female | 1.056 | 63.2 | 918 | 63.1 | 841 | 63.5 | 761 | 65.2 |
Profile | ||||||||
 E-Profile | 847 | 50.7 | 740 | 50.9 | 678 | 51.2 | 590 | 50.6 |
 M-Profile | 824 | 49.3 | 714 | 49.1 | 646 | 48.8 | 577 | 49.4 |
| Â | M | SD | M | SD | M | SD | M | SD |
|---|---|---|---|---|---|---|---|---|
Age | 16.9 | 1.5 | 18.1 | 1.5 | 19.1 | 1.5 | 19.4 | 1.5 |