Dear Dr. Dalgaard Sorry for delay reply.. That's exactly what I was looking for - thanks a lot.
Hsin-Ya Peter Dalgaard wrote: > > <oops, this got sent as reply to Andrew only> > > Andrew Robinson wrote: >> In your data, subject is nested within sequence. Was that your >> intention? >> >> > Presumably yes. This looks like a standard cross-over design. > > I fail to see what the interaction between subject and sequence might > mean, so I also have no idea what SPSS might have done. (The list does > not allow .doc attachments). > > Since this is a balanced design, you can get almost the right analysis by > >> m <- lm(Max ~ sequence + subject + period + > + drug, data=Data) >> anova(m) > Analysis of Variance Table > > Response: Max > Df Sum Sq Mean Sq F value Pr(>F) > sequence 1 585 585 0.0160 0.9014 > subject 12 634325 52860 1.4469 0.2660 > period 1 63175 63175 1.7293 0.2131 > drug 1 58149 58149 1.5917 0.2311 > Residuals 12 438395 36533 > > in which you have to know that sequence is aliased with the drug:period > interaction, AND that it needs to be compared with the intersubject > variation. I.e. the F test is wrong and should be replaced with F= > 585/52860 = 0.011on 1 and 12 df. > > However, a better way is > >> summary(aov(Max ~ period*drug + Error(subject), data=Data)) > > Error: subject > Df Sum Sq Mean Sq F value Pr(>F) > period:drug 1 585 585 0.0111 0.918 > Residuals 12 634325 52860 > > Error: Within > Df Sum Sq Mean Sq F value Pr(>F) > period 1 63175 63175 1.7293 0.2131 > drug 1 58149 58149 1.5917 0.2311 > Residuals 12 438395 36533 > > > > -- > 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 > ~~~~~~~~~~ - ([EMAIL PROTECTED]) 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. > > -- View this message in context: http://www.nabble.com/Problems-with-lm%28%29-tp17999900p18229758.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
