Figure 2.

Cluster analysis based on participants’ weekly ratings. (a) Illustrates the average silhouette width (Y-axis)³⁵ as a function of the number of clusters (X-axis); the blue point (n = 3) represents the natural number of clusters determined by the silhouette width. Based on the usage patterns, we call these clusters: low-, medium-, and high-usage clusters. (b)(c)(d) Illustrate the weekly ratings for participants of the low-, medium-, and high-usage clusters, respectively; for each plot, the X-axis is the week and the Y-axis is the weekly rating for each of the cluster’s participants, with each line representing a participant.