PSQI (n = 226) Χ2 value φ P value PSQI ≥ 6 PSQI < 6 (n = 8) (n = 218) n % Adjusted residual n % Adjusted residual Breakfast (n = 226) I eat breakfast every morning. 6 2.65 −1.6 199 88.05 1.6 0.88 −0.10 0.16 I sometimes do not eat breakfast. 2 0.88 1.6 19 8.41 −1.6 Bowel movement (n = 226) I have bowel movement every day. 4 1.77 −0.5 130 57.52 0.5 0.03 −0.04 0.72 I do not have bowel movement every day. 4 1.77 0.5 88 38.94 −0.5 School meal (n = 226) I always eat a full school meal. 5 2.21 0.0 136 60.18 0.0 0.00 0.00 1.00 I sometimes leave part of a school meal. 3 1.33 0.0 82 36.28 0.0 Snack (lunch to dinner) (n = 226) I eat a snack four days or more a week. 4 1.77 0.7 82 36.28 −0.7 0.11 0.05 0.48 I eat a snack less than three days a week. 4 1.77 −0.7 136 60.18 0.7 Snack (dinner to fall asleep) (n = 226) I eat a snack four days or more a week. 1 0.44 0.6 15 6.64 −0.6 0.00 0.04 0.45 I eat a snack less than three days a week. 7 3.10 −0.6 203 89.82 0.6 Exercise (n = 226) I exercise three or more days a week. 6 2.65 −0.2 170 75.22 0.2 0.00 −0.01 1.00 I exercise less than two days a week. 2 0.88 0.2 48 21.24 −0.2 Cram school (n = 226) I am going to cram school. 5 2.21 0.9 101 44.69 −0.9 0.29 0.06 0.48 I am not going to cram school. 3 1.33 −0.9 117 51.77 0.9 Physical strength (n = 225) High 2 0.89 1.6 117 52.00 −1.6 1.56 0.11 0.15 Low 6 2.67 −1.6 100 44.44 1.6 Falling asleep* (n = 177) I could fall asleep quickly. 1 0.56 −2.7 152 85.88 2.7 3.46 −0.20 0.05 I had difficulty sleeping. 2 1.13 2.7 22 12.43 −2.7 Wake up** (n = 105) I woke up feeling refreshed. 2 1.90 −2.0 79 75.24 2.0 2.19 −0.20 0.08 I was sleepy. 3 2.86 2.0 21 20.00 −2.0