Suppose I do a trigonometric regression fit<-lm(y~ cf + sf) where cf and sf are the cos and sine components.
b<-coef(fit) I have the fitted sine component b[2] and the cos component b[3]. Doing summary(fit) gives me the p-values and SEs for b[2] and b[3]. But I want the amplitude of the fitted waveform amp<-sqrt(b[2]^2+b[3]^2) Can someone please tell me how to get the p-value for amp? Thanks. Bill ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.