Figure 2

Computing the correlation between clinical parameters and microarray data. The Normalized Tree Index (NTI) is used to compute a correlation coefficient between the clustering result (tree structure) of high-dimensional primary data (microarray data) and associated nominal labels of secondary data (clinical parameters). In a first step, the microarray data is clustered by hierarchical agglomerative clustering using standard settings. In a second step, the computed cluster tree is evaluated using the NTI. For each label, a NTI is computed that measures the correlation between that label and the clustered microarray data. This permits the identification of labels that are highly correlated with the microarray data, while analyzing the microarray data in its entirety.