Table 1.

Logistic GAMM of the association between current sleepiness and probability of future social activity at different times of day

Variable	Estimate	SE	t-value	P value
Parametric coefficients
Intercept	−1.78	0.06	−31.72	<0.001
Workday	−1.02	0.05	−19.66	<0.001
Smooth terms	EDF	RefDF	F-value
Sleepiness [workday]	0.97	4	7.78	<0.001
Sleepiness [freeday]	2.87	4	61.50	<0.001
Time of day	2.98	3	349.37	<0.001
Sleepiness × time of day	7.15	12	6.18	<0.001
Random intercept for participant	375.79	483	3.71	<0.001

GAMM, generalized additive mixed-effect model; EDF, effective degrees of freedom; RefDF, reference degrees of freedom. Smooth terms with categorical moderators, as specified in square brackets, represent separate smoothing terms given the moderator’s condition. An “x” between two variables represents a continuous interaction. All values are on the logit scale. All smooth terms are centered around zero. P values for smooth terms represent a test of whether the term is different to a flat line.