In open source data mining software Weka (written in Java), when I run some data mining algorithm like Linear regression Weka returns model and some model evaluating metrics for test data.
It looks like this:
Correlation coefficient 0.2978 Mean absolute error 15.5995 Root mean squared error 29.9002 Relative absolute error 47.7508 % Root relative squared error 72.2651 %
What is the formula for "Relative absolute error" and "Root relative squared error"? I cannot figure that out. I would like to use this metrics to evaluate my own algorithms in Matlab.