Fig. 4 

Two-dimensional hierarchical clustering heatmap of H. pylori risk factors and feature selection methods. Maroon and blue colors indicate more and less frequently selected features in five tenfold cross-validation runs, respectively. X-axis shows the H. pylori risk factors, summarized in Table 1. Y-axis indicates all feature selection methods. The risk factors found more frequently by feature selection methods appear on the heatmap's left columns. The feature selection methods that select the greatest number of risk factors appear on the heatmap's bottom rows. The risk factors grouped together suggest that they have been chosen similarly under varying feature selection methods. The feature selection methods grouped together indicate that these methods choose a similar set of risk factors