This node is applicable only for continuous models (not classification).
For the specific nodes there are 3 inputs:
0 Values for the dependent variable, predicted by the model (ypred)
1 Values for the dependent variable for the test set (yexp)
2 Values for the dependent variable for the training set (ytr)
For each input you need one vector (the dependent variable) not the descriptors.
Please note that you need to pass to the node only values of the dependent variable not the whole data (you can put a splitter before the node for this job).
The values of the dependent variable are also needed, please have a look at the attached paper in which Tropsha’s equations are included (eq. 3, 4 & 5).
Since there are several questions about the training set. The training set (ytr) is used in equations 1 and 3 (actually what is used is the averaged value for the dependent variable for the training set).