On 7/12/07, Terry Therneau <[EMAIL PROTECTED]> wrote: > The question was how to get the p-value from the fit below, as an S object > > sr<-survreg(s~groups, dist="gaussian") > Coefficients: > (Intercept) groups > -0.02138485 0.03868351 > > Scale= 0.01789372 > > Loglik(model)= 31.1 Loglik(intercept only)= 25.4 > Chisq= 11.39 on 1 degrees of freedom, p= 0.00074 > n= 16 > > > ---- > In general, good places to start are > > names(sr) > > help(survreg.object) > > ssr <- summary(sr) > > names(ssr) > As someone else pointed out, it's also easy to look at the print.survreg > function and see how the value was created -- one of the things I love > about S. > > Unfortunately, doing the above myself showed that I have let the documentation > page for survreg.object get seriously out of date -- quite embarassing as > that is logically the first place to start. > > As to the print function creating things "on the fly": there is an area where > there is no good answer. Does one make the return object from a fit such > that it contains only minimal data, or add in all of the other computations > that can be derived from these? The Chambers and Hastie book "Statistical > Models in S", which was the starting point for model objects, leaned towards > the former, and this still influences many functions. Often the summary > function will "fill in" these derived values, the std and t-tests for > the individual coefficients for instance.
I think this is where it's nice to have a separate function that does the filling in - then you can have the best of both worlds. That's the role that summary often plays. Hadley ______________________________________________ [email protected] 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.
