Questionnaire about mobile phones
25
24
14
21
15
25
33
19
20
19
21
20
21
22
40
17
16
20
18
29
15
20
22
21
34
22 years
19
21
20
20
22
22
24
21
22
26
21
22
7
22
21
23
22
22
54
23
17
17
22
19
16
33
17
21
18
14
23
16
12 weeks
18
14
15
17
19
16
16 years
17
16
19
19
18
15
21
18
40
16
16
22
18
16 years old
26
30
20
37
20
16
17
20
18
16
24
20
16
21
17 years old
18
20
13
21
56