Add a feature to detect outliers in a data set. See e.g.
http://eurekastatistics.com/using-the-median-absolute-deviation-to-find-outliers
http://eurekastatistics.com/using-mahalanobis-distance-to-find-outliers
http://www.itl.nist.gov/div898/handbook/eda/section3/eda35h.htm
http://de.mathworks.com/help/curvefit/removing-outliers.html
and the papers cited therein.
Provide the access in the context menu of Column to this functionality. Open a dialog to show the found outliers and ask the user what to do with them:
1. mask them
2. remove them
3. do nothing
Alternatively, finding of the outliers can be implemented as a new analysis function in the plot/curve.