corresponding vector of markdowns, ?? is a shared price sensitivity factor, and ?? is a vector of n shared seasonal indices; determining adjusted , R2=1???(1???R2)*(n???1)/(n???1???c), where n is a number of observations, and c is a number of coefficients estimated, R2 being one of a measure of compactness of the cluster and an average cluster score; and one of using an array [??, ??] to define t