Dear R users, The package 'mfp' that fits fractional polynomial terms to predictors. Example: data(GBSG) f <- mfp(Surv(rfst, cens) ~ fp(age, df = 4, select = 0.05) + fp(prm, df = 4, select = 0.05), family = cox, data = GBSG) print(f)
To describe the association between the original predictor, eg. age and risk for different values of age I can plot it the polynomials and fitted coefficients as: plot(0.407*I((age/100)^-2) + -4.96*I((age/100)^-0.5) ~ age, GBSG) But I can't work out how to get a 95% confidence interval for this curve... Any suggestions? I could bootstrap it, but is there a mathematical solution? Many thanks Eleni Rapsomaniki Medical Statistician UCL, London ______________________________________________ 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.