Changes

''Correlation type distance''

''Correlation type distance''

:<math>\mathbf{Equation}</math>

:<math>d_{ll'} = \frac{\displaystyle\sum_{i = 1}^Px_{il}x_{il'}}{\sqrt{\displaystyle\sum_ix_{il}^2\displaystyle\sum_ix_{il'}^2}}</math>

One can also define a distance ''d''_ii&prime; between any two variables ''x''_''i'' and ''x''_i&prime; 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''_ii&prime; between any two variables ''x''_''i'' and ''x''_i&prime; 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.