tsunhin wong wrote:
Dear R users,I have copied for following table from an article on "Using confidence intervals in within-subject designs": Subject 1sec 2sec 5sec 1 10 13 13 12.00 2 6 8 8 7.33 3 11 14 14 13.00 4 22 23 25 23.33 5 16 18 20 18.00 6 15 17 17 16.33 7 1 1 4 2.00 8 12 15 17 14.67 9 9 12 12 11.00 10 8 9 12 9.67 I rearranged the data this way:subject<-factor(c(1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10)) condition<-factor(c(1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,5,5,5,5,5,5,5,5,5,5)) recall<-factor(c(10,6,11,22,16,15,1,12,9,8,13,8,14,23,18,17,1,15,12,9,13,8,14,25,20,17,4,17,12,12)) example<-cbind(subject,condition,recall)Using ANOVA (aov), I should have DF for condition = 2, DF of subjects = 9, Interaction DF = 18 And a term for mean square of interaction. (0.61)
Your data are not factors when you get to use them, hence the 1DF. It is the cbind() that is doing you in. Try
example <- data.frame(subject,condition,recall) However, "recall" should _not_ be a factor. -p
But, I have something like below instead:aov.recall <- aov(recall~condition + Error(subject/condition),data=as.data.frame(example)) summary(aov.recall)Error: subject Df Sum Sq Mean Sq F value Pr(>F) Residuals 1 12.898 12.898 Error: subject:condition Df Sum Sq Mean Sq condition 1 34.505 34.505 Error: Within Df Sum Sq Mean Sq F value Pr(>F) condition 1 3.22 3.22 0.1378 0.7135 Residuals 26 607.54 23.37 The within-subject (repeated measure) anova of R seems to be a bit subtle for me, please point out the errors that I have made if you can. Thank you very much! - John ______________________________________________ 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.
-- O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalga...@biostat.ku.dk) FAX: (+45) 35327907 ______________________________________________ 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.
