TABLE 2.

Coefficients for bed time.

	Estimate (β)	Standard error	T Value	Pr (>|t|)
Intercept	22.4144616	0.2160384	103.752
Day type (WD)	−0.9118506	0.0154273	−59.106	<2.2e-16
Work start time (h)	0.1997113	0.0058039	34.410	<2.2e-16
Work end time (h)	0.0031239	0.0040538	0.771	0.4409
Alarm clock usage (Yes)	−0.1039529	0.0180572	−5.757	8.568e-09
Age (year)	−0.0212709	0.0008845	−24.047	<2.2e-16
Gender (men)	0.3473451	0.0213046	16.304	<2.2e-16
Sunset time (h)	0.0557868	0.0103448	5.393	6.49e-08