Hi I have two questions regarding the meaning of intercept outputs of lm.
Question 1: In data set 1 (a fully-balanced design), the line with (Intercept) contains the overall mean, and the estimates contain the differences from the overall mean (matching those from model.tables). But in data set 2, the line with the intercept does not correspond to the overall mean and the estimates don't correspond to the differences outputted by model.tables. What does the output contain here? ##### rm(list=ls(all=TRUE)) options(contrasts=c("contr.sum", "contr.poly")) # data set 1 Y1<-c(43, 23, 88, 45, 2, 68, 39, 41, 55, 64, 91, 9, 90, 37, 88, 41) M1<-factor(c("k", "g", "k", "g", "k", "k", "g", "g", "g", "g", "k", "k", "g", "g", "k", "k")) N1<-factor(c("k", "g", "g", "k", "k", "g", "k", "g", "k", "g", "g", "k", "g", "k", "g", "k")) # linear model 1 model1<-lm(Y1~M1*N1); summary(model1) model.tables(aov(Y1~M1*N1), "means") model.tables(aov(Y1~M1*N1)) # data set 2 Y2<-c(34, 16, 46, 5, 2, 78, 31, 39, 25, 64, 45, 92, 65, 91, 60, 12, 33, 40, 72, 61, 49, 59) M2<-factor(c(rep("a", 10), rep("b", 12))) N2<-factor(c(rep("d", 4), rep("e", 6), rep("d", 8), rep("e", 4))) # linear model 2 model2<-lm(Y2~M2*N2); summary(model2) model.tables(aov(Y2~M2*N2), "means") model.tables(aov(Y2~M2*N2)) ##### Question 2: what does the line with (Intercept) mean that the following lines produce? ##### library(car) Anova(model, type=c("III")) ##### Any help would be much appreciated. Thx, STG ______________________________________________ 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.