. 2019 Oct 30;7(10):e13978. doi: 10.2196/13978

Table 7.

Fixed effects of the linear multilevel model evaluating the time trend of perceived stress- levels (PSS-4) while using TrackYourStress including the total scale of the Perceived Stress. Reactivity Scale as z-standardized time-invariant covariate.

Fixed effects	Estimate	SE	Values
Fixed effects	Estimate	SE	t test (df)	P value
Intercept	5.393	0.318	16.958 (78.225)	<.001
PSRS total^a	1.171	0.320	3.658 (78.317)	<.001
Time	−0.002	0.013	−0.186(65.547)	.85
Time × PSRS total	0.008	0.013	0.613 (68.266)	.54

^aPSRS total: Perceived Stress Reactivity Scale total score.