One can also define a distance ''d''<sub>ii′</sub> between any two variables ''x''<sub>''i''</sub> and ''x''<sub>i′</sub> by setting the previous summations over all n samples. Such distances between variables lead to definition of classes of variables having similar sample values. Such classes (clusters) of variables can help defining subsets of the P variables for further studies, with reduced dimensionality. | One can also define a distance ''d''<sub>ii′</sub> between any two variables ''x''<sub>''i''</sub> and ''x''<sub>i′</sub> by setting the previous summations over all n samples. Such distances between variables lead to definition of classes of variables having similar sample values. Such classes (clusters) of variables can help defining subsets of the P variables for further studies, with reduced dimensionality. |