Q1: How frequently do you use mobile phone per week?

1) every day

2) 4 - 5 times

3) 2 - 3 times

4) 0 - 1 time

Q2: What time do you mainly use mobile phones in weekdays? (multiple answers available)

1) 6:00 ~ 9:00

2) 9:00 ~ 12:00

3) 12:00 ~ 15:00

4) 15:00 ~ 18:00

5) 18:00 ~ 21:00

6) 21:00 ~ 24:00

7) 24:00 ~ 3:00

8) 3:00 ~ 6:00

Q3-1: On the usage of mobile phone between bedtime to wake-up time,

where do you put your mobile phone when you go to bed?

1) in the bed (e.g. near to head)

2) far from the bed but inside bedroom

3) other rooms than bed room

Q3-2: When you are going to fall in sleep in the bed and phone from mobile phone rings

(including mail, LINE and so on), how do you respond to it?

1) Respond to it soon,

2) Check it but no response,

3) No attention but sleep

Q4: How long per one usage do you use mobile phone in weekdays?

1) within

2) 10 ~ 30 min

3) 30 min ~ 1 h

4) >1 h

5) 1 - 2 hours

6) 3 hours or more