[R] help about 2 way anova and tukey test Dears members of R list, I have a technical question about conducting 2 way analysis of the variance  (ANOVA) for repeated measures followed tukey test using R. my data are:  There were 3 subj in all and 3 repeated measures for every time and therapy therapy = a,b,c time    = t1,t2,t3 subj    = 1,2,3 subj	therapy	t0	t1	t2 1	a	80.5	82.2	54.23 2	a	84.9	85.6	56.83 3	a	81.5	81.4	54.30 1	b	83.8	95.2	59.67 2	b	83.3	94.3	59.20 3	b	86	91.5	59.17 1	c	80.7	80.2	53.63 2	c	89.4	80.1	56.50 3	c	91.8	86.4	59.40 the code that I use is: rm(list=ls(all=TRUE)) dati<- read.table("dati.txt", T) attach(dati) subj<- c( 1: 9, 1: 9,1:9) therapy<- factor( c( rep(" a", 3), rep(" b", 3), rep(" c", 3),                      rep(" a", 3), rep(" b", 3), rep(" c", 3),                      rep(" a",3), rep(" b", 3), rep(" c", 3))) time<- factor( c( rep(" t0", 9), rep(" t1", 9),rep(" t2", 9))) weight<- c( t0,t1,t2) time <- factor( time) therapy <- factor( therapy) subj <- factor( subj) summary( fm1<-aov( weight~time*therapy)) fm1Tukey=TukeyHSD(fm1,"therapy",ordered = TRUE) ; fm1Tukey fm1Tukey=TukeyHSD(fm1,"time",ordered = TRUE) ; fm1Tukey fm1Tukey=TukeyHSD(fm1,"time:therapy",ordered = TRUE) ; fm1Tukey My question is - is that the correct way to do it??  Very much obliged for your kind response Maurizio ****************************************************************************** Maurizio Sarti, PhD IREA - CNR via Diocleziano,328 I-80124 Napoli (Italy) tel:+39-(0)81-5707999-(0)81-5704945  fax:+39-(0)81-5705734   cell:+39-3204397891 ****************************************************************************** e-mail: sarti.m@irea.cnr.it website: http://www.irea.cnr.it ______________________________________________ R-help@stat.math.ethz.ch 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.