Hi the list... I am working on cluster analysis, more precisely on Calinski and Harabasz criterion ( C(g)=Trace(between)/Trace(Within)*(n-g)/(g-1)) ) Is there a package for calculating within and between matrix? Morever, when we are using matrix with missing value, how do they handle it? On a more theorical point of view, how shall we do? Imputation will probably underestimate it, isn't it ? Christophe ---------------------------------------------------------------- Ce message a ete envoye par IMP, grace a l'Universite Paris 10 Nanterre