Table 1.
Sample characteristics and group differences at T0 participation.
| Sample characteristics | App group | Nonapp group | Significancea (app vs nonapp group) | Effect size, r | ||
|
|
VS1b | HS1c | VS2d | HS2e |
|
|
| T0 participation, N | 148 | 107 | 71 | 60 | N/Af | N/A |
| Age, mean (SD) | 16.7 (0.9) | 16.5 (1) | 16.9 (1) | 17.2 (0.7) | t=−4.31; P<.001 | .23 |
| Male participants, n (%) | 131 (89.1) | 54 (50.9) | 70 (98.6) | 24 (40) | χ21=0.1 | .01 |
| Repetition of year of study because of failure, n (%) | 13 (8.8) | 1 (0.9) | 5 (7) | 0 (0) | χ21=0.5 | .04 |
| Perceived socioeconomic status, mean (SD) | 4.5 (0.9) | 4.9 (0.9) | 4.5 (1.0) | 4.6 (1.0) | U=15,387.5 | .06 |
| Exercise frequency (minutes/day), mean (SD) | 103.9 (91.9) | 92.8 (51.9) | 169.5 (250.3) | 82.9 (47.4) | t=−2.12; P=.40 | .10 |
aIndependent sample t-test or Mann-Whitney U test or χ2 test or Fisher exact test.
bVS1: vocational school 1.
cHS1: high school 1.
dVS2: vocational school 2.
eHS2: high school 2.
fN/A: not applicable.