TABLE 4.

Coefficients for time in bed.

	Estimate (β)	Standard error	T Value	Pr (>|t|)
Intercept	9.2641588	0.1778633	52.086
Day type (WD)	−0.8613106	0.0173614	−49.611	<2.2e-16
Work start time (h)	0.0628613	0.0047751	13.164	<2.2e-16
Work end time (h)	0.0083555	0.0033355	2.505	0.01224
Alarm clock usage (Yes)	−0.3624247	0.0192046	−18.872	<2.2e-16
Age (year)	−0.0175093	0.0007306	−23.967	<2.2e-16
Gender (men)	−0.2349314	−0.2349314	−13.404	<2.2e-16
Sunset time (h)	−0.0362501	0.0085102	−4.260	2.048e-05