Thomas Chu wrote: > > Neither of those 3 lines of commands managed to drop x4 and its P value > magically decreased from 0.94 to almost 0! I am also baffled by how R > calculated those RSS. > Maybe it is using a different type of SS. If i have a lm() model, and i do: options(contrasts=c("contr.sum", "contr.poly")); anovafit <- drop1(model,attributes(model$terms)$term.labels,test="F"); then i get identical SS, F and p values as in SPSS. Maybe http://www.nabble.com/set-type-of-SS-in-anova()-to18287076.html#a18287076 this post is helpfull. Also check out the post on http://myowelt.blogspot.com/ this blog from 2008-05-24: Obtaining the same ANOVA results in R as in SPSS - the difficulties with Type II and Type III sums of squares .
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