Peter Dalgaard wrote: > Prof Brian Ripley wrote: > >> I think you will find that 'n' is used in several ways in predict.lm, >> and since NA-handling was introduced in R 1.8.0 they may differ in >> value. So the safest route seems to be to change just 'n' in >> >> df <- n - p > > Yes, that seems to fix things. Will commit to R-devel shortly. > > -p >
Spoke too soon, it fixes Bill's case, but breaks one of the regression tests! In fact this goes deeper, summary.lm special-cases the same zero-rank case by using length(residuals), so it also miscalculates with zero weights: > fit <- lm(y~0,weights=c(0,rep(1,9))) > summary(fit) Call: lm(formula = y ~ 0, weights = c(0, rep(1, 9))) Residuals: Min 1Q Median 3Q Max -1.95428 -1.40571 -0.42378 -0.05795 1.05518 No Coefficients Residual standard error: 1.119 on 10 degrees of freedom ---- Hum. lm() actually returns df.residual, AFAICS in all cases, now why don't we just use that throughout???? -- Peter Dalgaard Center for Statistics, Copenhagen Business School Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel