Figure 4.

Evolution of PROMIS Stress 4a between the three-arms during the study period. The plot illustrates the interaction between treatment (Sleep A; Arm 1 and Sleep B; Arm 2) and week on the stress scale, based on a linear mixed-effects model. The x-axis represents the weeks of the study, while the y-axis represents the outcome scale. The lines represent the trajectories of stress for each treatment arm over time. The plot highlights the nature of treatment effects on stress as captured by the linear mixed-effects model, allowing for the incorporation of random effects and accounting for within-subject correlations.