Fig 1.
Statistical framework of latent growth-curve model.
y represents the time-varying dependent variable such as daily activity, steps, active minutes, and activity calories; x represents the time-varying covariate among social, environmental, and behavioral factors that change on a daily basis; z represents the time-constant covariate among personal and cognitive factors that are stable over time; and η0 and η1 represent the latent variables for the intercept and linear slope of the dependent variable y, respectively.
Table 1.
Summary statistics for time-varying variables.
Table 2.
Summary statistics for time-constant variables.
Fig 2.
Scatter plot and linear prediction plot with 95% confidence interval for each of the four dependent variables.
a. Physical activity; b. Steps; c. Active minutes; d. Activity calories.
Table 3.
Parameters and 95% confidence intervals from the latent growth-curve models.