Jack: You are confused!
You have specified that the factor is ordered (ordered = TRUE), so you do _not get_ the (6, not 7 btw)single degree of freedom contrasts corresponding to weekday names. Instead you get the (default) contrasts for an ordered factor (.L = linear, .Q = quadratic, etc.). Also you apparently do not have all weekdays present or maybe there is partial confounding with some of your other factors, thus producing the singularities given in the message. While you can read up on such matters ("contrasts") in the docs and texts about R (V&R's MASS has a nice explanation), these issues are inherently technical. So if you do not have the requisite statistical background, I suggest you consult a statistician. To paraphrase an R fortune -- if you do not know how to properly use the statistical tools, you shouldn't be using them. Cheers, Bert Gunter Genentech Nonclinical Biostatistics -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Jen-Chien Chang Sent: Monday, November 02, 2009 7:02 AM To: r-help@r-project.org Subject: [R] how to print the full name of the factors in summary? Hi, I am wondering if there is a simple way to fix the problem I am having. For unknown reason, I could not get the full name of the factors to be printed in the summary. I have tried to used summary.lm as well but the problem still persists. SJ$Weekday <- factor(SJ$Weekday,1:7,c("Mon","Tue","Wed","Thu","Fri","Sat","Sun"),ordered=T ) .... attach(SJ) lm.SJ <- lm(Demand ~ Weekday+Month+Holiday+Season) summary(lm.SJ) Call: lm(formula = Demand ~ Weekday + Month + Holiday + Season) Residuals: Min 1Q Median 3Q Max -69.767 -12.224 -1.378 10.857 91.376 Coefficients: (3 not defined because of singularities) Estimate Std. Error t value Pr(>|t|) (Intercept) 88.7091 3.3442 26.527 < 2e-16 *** Weekday.L 20.8132 2.8140 7.396 1.08e-12 *** Weekday.Q -12.7667 2.8156 -4.534 7.99e-06 *** Weekday.C -10.6375 2.8113 -3.784 0.000182 *** Weekday^4 -8.3325 2.8103 -2.965 0.003238 ** --------------------------------------------- Is there a way for summary to print the full name of the factors and levels? Say Weekday.Tue instead Weekday.L? Thanks! Jack Chang ______________________________________________ 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.