On Dec 1, 2010, at 9:18 AM, Peter Ehlers wrote:
It might be a good idea not to use an outdated version of R. I don't see your "problem" in R 2.12.0.
Furthermore isn't it a bit <something> to be asking why the sign on a number that is effectively zero happens to be negative? I would think that FAQ 7.31 applied even back in the 2.9 and 2.10 era.
(I still get a negative number in R 2.12.0 that is effectively zero, -4.4409e-16, and rounded is exactly the same as the difference between sqrt(2)^2 and 2 in the FAQ entry, so if it were supposed to be "fixed" (which I'm not saying it should be) then it didn't occur until very recently.)
-- David.
Peter Ehlers On 2010-12-01 05:44, jean.cour...@math.u-psud.fr wrote:Just for fun This small program gives negative Sum of Sq in anova (with R versions 2.9.2 and 2.10.0) (linux 32 kernel 2.6.29.6-smp slackware 13.0) : y = c(3.6, 5.0, 5.0, 4.6, 4.5, 4.3, 4.5, 5.1, 4.5, 4.3) trans = as.factor(c("NT","NT","NT","NT","NT","T","T","T","T","T")) lc = lm(y ~ trans) l1 = lm(y ~ 1) anova(l1,lc) # Analysis of Variance Table # # Model 1: y ~ 1 # Model 2: y ~ trans # Res.Df RSS Df Sum of Sq F Pr(>F) # 1 9 1.744 # 2 8 1.744 1 -2.220e-16 # negative Sum of Sq ???? anova(lc) # is OK # 2.9.2 version # Analysis of Variance Table # # Response: y # Df Sum Sq Mean Sq F value Pr(>F) # trans 1 8.214e-32 8.214e-32 3.768e-31 1 # Residuals 8 1.744 0.218 # 2.10.0 version # Analysis of Variance Table # # Response: y # Df Sum Sq Mean Sq F value Pr(>F) # trans 1 0.000 0.000 0 1 # Residuals 8 1.744 0.218 ______________________________________________ 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.______________________________________________ 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.
David Winsemius, MD West Hartford, CT ______________________________________________ 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.
