Table 4. Bivariate associations between study variables.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | ||
| 1 | Age D1 | - | -.31** | .06 | .36** | .08 | .16* | .13 | .08 | .03 | .02 | .06 | .06 |
| 2 | Age D2 | - | .04 | .25** | .06 | .11 | .13 | .22** | .17* | .01 | -.07 | -.20** | |
| 3 | Gender | - | .07 | .04 | .07 | .06 | -.07 | .01 | .09 | -.07 | .01 | ||
| 4 | Marital status | - | .08 | .21** | .18** | .22** | .17* | .05 | -.01 | -.02 | |||
| 5 | Sleep quality | - | .30** | .36** | .57** | .38** | .29** | .46** | -.36** | ||||
| 6 | Chronotype (Morningness) | - | .22** | .27** | .37** | .05 | .12 | -.28** | |||||
| 7 | Trait self-control | - | .20** | .22** | .16* | .16* | -.15* | ||||||
| 8 | SH1 | - | .42** | .23** | .33** | -.29** | |||||||
| 9 | SH2 | - | .28** | .20** | -.26** | ||||||||
| 10 | SH3 | - | .33** | -.15* | |||||||||
| 11 | SH4 | - | -.26** | ||||||||||
| 12 | Bedtime media use | - |
Note. Age D1 was coded as 0 for 21–30 years and 1 for 31–50 years, whereas age D2 was coded as 0 for 21–30 years and 1 for 50 years or above. Gender was coded 0 for men and 1 for women. Marital status was coded as 0 for single, divorced or widowed and 1 for married. SH1 = pre-sleep stress management, SH2 = sleep timing regularity, SH3 = avoiding sleep-disrupting food or activities, SH4 = keeping a restful sleep environment.
*p < .05.
**p < .01.