Table 3.

GAMM of the association between intraindividual sleep duration and the amount of future social activity (in individuals who socialize at least once)

Variable	Estimate	SE	t-value	P value
Parametric coefficients
Intercept	1.88	0.02	81.98	<0.001
Workday	−0.54	0.02	−21.98	<0.001
Smooth terms	EDF	RefDF	F-value
Sleep duration	0.00	4	0.00	0.563
Average sleep duration	1.69	4	8.51	0.019
Sleep duration × average sleep duration	1.72	16	0.65	0.010
Random intercept for participant	237.90	437	1.57	<0.001

GAMM, generalized additive mixed-effect model; EDF, effective degrees of freedom; RefDF, reference degrees of freedom. An “x” between two variables represents a continuous interaction. All smooth terms are centered at zero. P values for smooth terms represent a test of whether the term is different to a flat line.