Table 3.
Results of the Stage 1 mixed-effects model and the Stage 2 multiple regression model
| Variable | ||||
|---|---|---|---|---|
| Stage 1 model | Estimate | 95% CI | Z | R 2 |
| Regression coefficients | ||||
| Intercept | 0.09*** | 0.07–0.11 | 8.03 | 0.17 |
| Physical context (outdoor = 1) | 0.07*** | 0.03–0.11 | 3.69 | |
| Weekday vs. weekend day (weekend = 1) | 0.01 | −0.02–0.03 | 0.39 | |
| Random location effects variance and covariances | ||||
| Random intercept | 0.01** | <0.01–0.02 | 3.14 | |
| Random slope | 0.02** | 0.01–0.03 | 3.02 | |
| Covariance (random intercept and slope) | <−0.01 | <−0.01–0.01 | −0.48 | |
| Error variance | 0.05*** | 0.04–0.06 | 22.04 | |
| Stage 2 model | ||||
| Intercept | 1.63*** | 1.22–2.04 | 7.71 | 0.27 |
| Sex (male = 1) | 0.17* | 0.04–0.30 | 2.55 | |
| Age | −0.01 | <−0.01–<0.01 | −1.08 | |
| Body mass index | −0.01 | −0.01–0.01 | −0.65 | |
| Random intercept (during baseline) | 0.15*** | 0.06–0.23 | 4.40 | |
| Random slope (during baseline) | 0.09* | 0.01–0.18 | 2.13 | |
| Error variance | 0.09*** | 0.06–0.11 | 6.88 | |
N of observations for Stage 1 model = 1,163. N of subjects for Stage 2 model = 108. The dependent variable for the Stage 1 mixed-effects model is the number of moderate-to-vigorous physical activity (MVPA) minutes in the 30 min window during the baseline ecological momentary assessment (EMA) period (a Level 1 variable). The dependent variable for the Stage 2 multiple regression model is the mean daily MVPA minutes in the 30 min window during the 6 month follow-up EMA period (a Level 2 variable). R2 = R-squared values for Stage 1 and Stage 2 models.
*p < .05, **p < .01, ***p < .001.