RapidMiner 9.8 Beta is now available
Be one of the first to get your hands on the new features. More details and downloads here:
best unbiased estimator vs second moment
A quite unimportant question:
Is there any specific reason why you use the second moment instead of the best unbiased estimator for variance ? I have often stepped over different calculations in different libaries, which sometimes caused a little headache "why the results differ now ?".