How to get Greenhouse-Geisser epsilons from anova?
Skotara wrote:
Dear John and Peter, thank you both very much for your help! Everything works fine now! John, Anova also works very fine. Thank you very much! However, if I had more than 2 levels for the between factor the same thing as mentioned occured. The degrees of freedom showed that Anova calculated it as if all subjects came from the same group, for example for main effect A the dfs are 1 and 35. Since I can get those values using anova that causes no problem. I saw that the x$G to get the greenhouse-geisser epsilon do work for: x<- anova(mlmfitD, X=~C+B, M=~A+C+B, test = "Spherical") but does not work for y$G: y <- anova(mlmfit, mlmfit0, X= ~C+B, M = ~A+C+B, idata = dd,test="Spherical")
Do yourself a favour and check what the actual names are: foo$"G-G Pr" works in both forms. Notice that these are the epsilon-corrected p-values, and not the epsilons themselves.
Finally, the Greenhouse-Geisser epsilons are identical using both methods and to the SPSS output. The Huynh-Feldt are not the same as them of SPSS. I will use GG instead.
If they differ by a factor of N/(f+1) where f is the number of df for the SSD matrix (alias N-k if all you have is a grouping into k groups), then SPSS has the same bug as SAS. (This is also mentioned in the R news paper).
O__ ---- Peter Dalgaard ?ster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907