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. 2020 Jan 24;22(1):e15438. doi: 10.2196/15438

Table 3.

Baseline characteristics of participants by condition.

Variable (number of missing values) Total (N=1247) Experimental group (n=742) Control group (n=505) Test statistic P value
Schools, n 15 8 7 N/Aa N/A
Classrooms per school, n 62 38 24 N/A N/A
Students per classroom, mean (SD), range N/A 19.53 (6.90), 25 21.04 (5.87), 26 N/A N/A
Age (15-19-year-olds) (0), mean (SD) 16.32 (1.07) 16.40 (1.06) 16.21 (1.06) Ub=208553;
t1245=–3.150
<.001;
.002
Gender (0), n (%)


χ21=0.2 .67

Male 586 (46.99) 345 (46.5) 241 (47.7)


Female 661 (53.01) 397 (53.5) 264 (52.3)

Educational level (0), n (%)


χ22=12.1 .002

Compulsory secondary education 545 (43.70) 321 (43.3) 224 (44.4)


Baccalaureate program 515 (41.30) 289 (38.9) 226 (44.8)


Vocational training 187 (15.00) 132 (17.8) 55 (10.9)

Religion (3), n (%)


χ24=3.1 .55

Catholic 767 (61.65) 462 (62.3) 305 (60.6)


Protestant or Evangelical 26 (2.09) 19 (2.6) 7 (1.4)


Muslim or Islamic 18 (1.45) 10 (1.4) 8 (1.6)


Other 28 (2.25) 15 (2.0) 13 (2.6)


No religion 405 (32.56) 235 (31.7) 170 (33.8)

Ethnicity (3), n (%)


χ21=1.9 .17

Spanish 1178 (94.69) 707 (95.4) 471 (93.6)


Non-Spanish 66 (5.31) 34 (4.6) 32 (6.4)

Apgar test (55), n (%)


χ21=2.2 .14

Functional family 886 (74.33) 516 (72.8) 370 (76.6)


Dysfunctional family 306 (25.67) 193 (27.2) 113 (23.4)

Family affluence (49)


χ22=3.5 .17

Low 33 (2.76) 17 (2.4) 16 (3.3)


Medium 387 (32.30) 244 (34.2) 143 (29.5)


High 778 (64.94) 452 (63.4) 326 (67.2)

Alcohol use (0)





Binge drinking, n (%) 487 (39.10) 298 (40.2) 189 (37.4) χ21=0.9 .33

Heavy episodic drinking, n (%) 16 (1.30) 8 (1.1) 8 (1.6) χ21=0.6 .44

Weekly consumption, mean (SD) 1.45 (4.30) 1.47 (3.78) 1.42 (4.96) U=190393.5
t1245=-0.2
.52
.84

Any consumption, n (%) 832 (66.70) 486 (65.5) 346 (68.5) χ21=1.2 .27

aNot applicable.

bMann-Whitney U test.