I have the following script, how can I implement to achieve that calculate the VIF. Thanks. U1.7km<-c(15:24) R<-c(1.2,0.2,3.6,2.5,4.8,6.3,2.3,4.1,7.2,6.1) Hm<-c(1:10) mod<-nls(R~a*(U1.7km^b)*(Hm^c), start=list(a=2.031, b=0.800, c=-0.255), trace=T) summary(mod) coef(mod) coef(summary(mod)) -- View this message in context: http://www.nabble.com/Variance-inflation-factors-%28VIF%29-tp22366713p22366713.html Sent from the R help mailing list archive at Nabble.com.