2.5. Statistical Analysis and Pre-Processing
Uncertain behavior
Data from the full analysis set, including subjects randomized and exposed to products within the intervention arms, were analyzed according to the intention-to-treat principle. Estimates are given as the mean ± standard error/standard deviation, (SE/SD). A Data pre-processing and analysis, including correlations, principal component analysis (PCA), and mixed-effects models were performed on R Studio [For bivariate analysis, such as correlation, we removed data points with z-scores that were greater than 3 or smaller than −3 standard deviations. For multivariate analysis, such as linear-mixed effect models, we removed multivariate outliers with a probability of occurring equally to or less than 1%, according to the Mahalanobis distance of that data point to the group centroid. All variables were mean centered before the correlation and linear-mixed effect analysis.To understand the relationship between lifestyle habits and psychological variables we reduced the dimensionality of the lifestyle variables using PCA. We grouped lifestyle variables based on available evidence, by whether they belonged to healthy, risky, or uncertain behaviors and ran a separate PCA for each of the three groups of variables. The component scores of the set of variables comprising healthy behaviors will be called “Health Behavior” (HB), the one from the set of variables comprising risk behaviors will be called “Risk Behavior” (RB) and the one from the set of variables comprising uncertain behaviors will be called “Uncertain behavior” (UB). Each of these three variables is a value that summarizes the lifestyle habits of each subject, according to the three categories of lifestyle habits. Details about the categorization and statistical procedures can be found in 