Ronan Conroy <[email protected]> replying to Adam Seth Litwin gives
good warning about F tests after a cluster analysis
> Careful. An analysis of variance is a hypothesis test. The model is
> specified in advance and the anova calculates the values of the model
> parameters.
>
> In your case, the model was generated from the data. The usual
> interpretation of the F ratio does not apply.
You may also want to look at the -cluster stop- command with the
-calinski- option. It provides the Calinski/Harabasz Pseudo-F
index. The word "Pseudo" is used to emphasize the point that
Ronan makes above.
The usual use of -cluster stop- is to compare the four group
versus five group versus six group cluster solutions (as an
example) for the clustering of a dataset so that you can decide
the most natural number of groups.
Ken Higbee
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