I try to move from SPSS to R/S and am trying to reproduce the results of SPSS in R. I calculated a one-way anova with "spk" as experimental factor and erp as depended variable. The result of the Anova are the same concearning the mean square, F and p values. But I also wanted to caculate the contr.sdif(4) contrast on spk. The results are completely different now. I hope anybody can help me.
Thanks, Wolfgang This is what I get in SPSS: Tests of Within-Subjects Contrasts Measure: MEASURE_1 Source SPKType III Sum of Squares df Mean Square F Sig. SPK Level 2 vs. Level 1 3,493 1 3,493 2,026 ,178 Level 3 vs. Previous 20,358 1 20,358 10,168 ,007 Level 4 vs. Previous 18,808 1 18,808 15,368 ,002 Error(SPK) Level 2 vs. Level 1 22,414 13 1,724 Level 3 vs. Previous 26,030 13 2,002 Level 4 vs. Previous 15,911 13 1,224 This is the result in R: Error: sub Df Sum Sq Mean Sq F value Pr(>F) Residuals 13 205.79 15.83 Error: Within Df Sum Sq Mean Sq F value Pr(>F) spk 3 29.425 9.808 9.4467 8.055e-05 *** spk: p 1 1.747 1.747 1.6821 0.2022649 spk: q 1 13.572 13.572 13.0719 0.0008479 *** spk: r 1 14.106 14.106 13.5861 0.0006915 *** Residuals 39 40.493 1.038 --- Signif. codes: 0 `***' 0.001 `**' 0.01 `*' 0.05 `.' 0.1 ` ' 1 Spk.df <- data.frame(sub,spk,erp) subset(Spk.df, subset=(sub!="14oddball" & sub!="18odd" & sub!="19odd" & sub!="20oddball")) -> Spk.selected.df contrasts(Spk.selected.df$spk) <- contr.sdif(4) aov(erp ~ spk + Error(sub), data=Spk.selected.df) -> Spk.aov summary(Spk.aov,data=Spk.selected.df,split=list(spk=list(p=1,q=2,r=3))) this is the the beginning of the dataframe, which I use: sub spk erp 1 10oddball spk1 2.587 2 11oddball spk1 -0.335 3 12oddball spk1 5.564 5 15oddball spk1 0.691 6 17oddball spk1 -1.846 10 21oddball spk1 1.825 11 22oddball spk1 0.370 12 2oddball spk1 3.234 13 3oddball spk1 1.462 14 5oddball spk1 2.535 15 6oddball spk1 9.373 16 7oddball spk1 2.132 17 8oddball spk1 -0.518 18 9oddball spk1 2.450 19 10oddball spk2 2.909 20 11oddball spk2 0.708 21 12oddball spk2 4.684 23 15oddball spk2 3.599 ... ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html