Fig. 2
From: A prospective observational study on trajectories and prognostic factors of mid back pain
Partition quality of cluster analysis. The x-axis shows the number of clusters, the y-axis the quality of the partition, which represents a combination of the within- and the between-cluster covariance. A high value indicates good partition quality. A two-cluster solution was favored by three criteria (1 = Calinski Harabatz 1; 4 = Ray Turi; 5 = Davies Bouldin), a six-cluster solution by two criteria (2 = Calinski Harabatz 2; 3 = Calinski Harabatz 3)