# Factor of t of the RMS deviation

What does it means when someone say that:

This value is defined as a factor of t of the RMS deviation of datapoints in the cluster from the centroid

Well, the RMSD between two vectors is defined here, but what does it mean when we say that a given value is a factor of t of the RMSD of datapoints from the centroid ?

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Any chance you've got a bit more context for this? – Matt Krause Apr 29 '12 at 22:29