Dear all, I want to select a linear model by means of a forward selection procedure, adding only the main terms, that is x1+x2+x3+...xn. Is there a fast way to specify all the main terms without writing each one? For example: linear <- step(lm(resp~1,data=dati),scope=(upper="all main effects",lower=~1),direction="forward") Thanks, Stefano ******************************* Stefano Calza Istituto di Statistica Medica e Biometria Universit? degli Studi di Milano Via G. Venezian, 1 20133 Milano tel. +39 02/2361302, 02/70600908 fax 02/2362930 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._