topic Re: Subtracting Within STD from Total STD in PROC FASTCLUS output? in Statistical Procedures

Subtracting Within STD from Total STD in PROC FASTCLUS output?

matt_dubins — Fri, 31 Jul 2015 12:35:08 GMT

Hello,

This pertains to the output data from PROC FASTCLUS. This may sound very ignorant, but I'm wondering if you get a measure of separation between clusters (a kind of "Between STD") when you subtract Within STD from Total STD? I would then be interested in the ratio between this "Between STD" vs Within STD. If not, should R^2 ratio be preferred as a measure of separation of clusters vs within cluster variation?

Thank you!

Re: Subtracting Within STD from Total STD in PROC FASTCLUS output?

Rick_SAS — Wed, 05 Aug 2015 20:12:28 GMT

The VariableStat table contains a column labeled RSQ/(1 - RSQ). The documentation says that that ratio is "the ratio of between-cluster variance to within-cluster variance." Is that what you are looking for?

I don't think what you suggest would be true (but I don't fully understand what you are proposing). In my experience, it is usually the VARIANCE (not the STD) that you try to decompose into interpretable independent components.