Calculate difference between target value en predicted value
I have a model with a target variable (type real) and a predicted variable.
I need an extra attribute in the result that calculates the absolute value of the difference from the predicted score and the actual score. How do I do this?
The way I am doing it now is to save the results in an Excel file and add an extra column and then calculate the difference. But I would like to do it directly in RM.