Table 2.
Sample characteristics and group differences at T1 participation.
| Sample characteristics | App group | Nonapp group | Significancea (app vs nonapp group) | Effect size, r | ||
|
|
VS1b | HS1c | VS2d | HS2e |
|
|
| T1 participation, N | 90 | 65 | 38 | 53 | N/Af | N/A |
| Age, mean (SD) | 16.7 (0.9) | 16.3 (0.9) | 16.7 (0.8) | 17.1 (0.7) | t=−3.29; P=.001 | .22 |
| Male participants, n (%) | 79 (87.8) | 33 (50.8) | 37 (97.4) | 18 (34) | χ21=3.7 | .12 |
| Repetition of year of study because of failure n (%) | 9 (10) | 1 (1.5) | 2 (5.3) | 0 (0) | P=.22 | N/A |
| Perceived socioeconomic status, mean (SD) | 4.4 (0.9) | 5 (0.9) | 4.3 (1.1) | 4.6 (0.9) | U=6230 | .10 |
| Exercise frequency (minutes/day), mean (SD) | 153.2 (208.9) | 88.3 (48.5) | 191.3 (257.5) | 84.6 (135.8) | t=−0.13 | .01 |
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.