Table 4.
GAMM of the association between preceding amount of social activity and future sleepiness at different times of day
Variable | Estimate | SE | t-value | P value |
Parametric coefficients | ||||
Intercept | −0.48 | 0.04 | −12.88 | <0.001 |
Workday | 0.47 | 0.05 | 9.51 | <0.001 |
Smooth terms | EDF | RefDF | F-value | |
Social activity [workday] | 0.00 | 4 | 0 | 1.00 |
Social activity [freeday] | 0.00 | 4 | 0 | 0.993 |
Time of day | 2.97 | 3 | 472.20 | <0.001 |
Social activity × time of day [workday] | 4.83 | 12 | 13.94 | <0.001 |
Social activity × time of day [freeday] | 5.46 | 12 | 4.78 | <0.001 |
Random intercept for participant | 161.80 | 462 | 0.60 | <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 smooth terms are centered at zero. P values for smooth terms represent a test of whether the term is different to a flat line.