Figure 2.

Data visualization in decibels (log₂ of the expression). HF is composed of 18 samples, LF 9 samples and Validation 17 samples. The phenotype of the validation samples is not used for learning purposes. The expression varies from 21 to 62.088, that is, a fold change of 11, 53. No filtering is performed in the expression data, since the feature selection methods that are used are robust to the presence of outliers. Also, the gene selection is not only based on differential expression that might be affected by the presence of noise.