Falling asleep (n = 177)*

Χ² value

φ

P value

I could fall asleep quickly.

I had difficulty sleeping.

(n = 153)

(n = 24)

n

%

Adjusted residual

n

%

Adjusted residual

Breakfast

(n = 177)

I eat breakfast every morning.

145

81.92

3.3

18

10.17

−3.3

11.13

0.25

0.00***

I sometimes do not eat breakfast.

8

4.52

−3.3

6

3.39

3.3

Bowel movement

(n = 177)

I have bowel movement every day.

100

56.50

1.5

12

6.78

−1.5

2.11

0.11

0.15

I do not have bowel movement every day.

53

29.94

−1.5

12

6.78

1.5

School meal

(n = 177)

I always eat a full school meal.

96

54.24

0.8

13

7.34

−0.8

0.65

0.06

0.42

I sometimes leave part of a school meal.

57

32.20

−0.8

11

6.21

0.8

Snack (lunch to dinner)

(n = 177)

I eat a snack four days or more a week.

61

34.46

0.2

9

5.08

−0.2

0.05

0.02

0.83

I eat a snack less than three days a week.

92

51.98

−0.2

15

8.47

0.2

Snack (dinner to fall asleep)

(n = 177)

I eat a snack four days or more a week.

10

5.65

−1.0

3

3.00

1.0

0.39

−0.08

0.39^a)

I eat a snack less than three days a week.

143

80.79

1.0

21

11.86

−1.0

Exercise

(n = 177)

I exercise three or more days a week.

126

71.19

1.8

16

9.04

−1.8

3.22

0.14

0.07

I exercise less than two days a week.

27

15.25

−1.8

8

4.52

1.8

Cram school

(n = 177)

I am going to cram school.

126

71.19

1.2

16

9.04

−1.2

1.51

0.09

0.22

I am not going to cram school.

27

15.25

−1.2

8

4.52

1.2

Physical strength

(n = 176)

High

90

51.14

1.2

11

6.25

−1.2

1.52

0.09

0.22

Low

62

35.23

−1.2

13

7.39

1.2