From: Christoph Scherber <Christoph.Scherber_at_agr.uni-goettingen.de>

Date: Thu, 17 Jul 2008 15:14:07 +0200

>> Dear Hsin-Ya Lee,

*>>
*

*>> The problem seems to be that every subject always only received one
*

*>> sequence:
*

*>>
*

*>> sequence
*

*>> subject 1 2
*

*>> 1 0 2
*

*>> 2 2 0
*

*>> 3 0 2
*

*>> 4 2 0
*

*>> 5 0 2
*

*>> 6 2 0
*

*>> 7 0 2
*

*>> 8 2 0
*

*>> 9 0 2
*

*>> 10 2 0
*

*>> 11 0 2
*

*>> 12 2 0
*

*>> 13 0 2
*

*>> 14 2 0
*

*>>
*

*>>
*

*>> You should try to use a design where each subject receives each of the two
*

*>> sequences. Otherwise
*

*>> obviously the interactions will be not available.
*

*>>
*

*>> Best wishes
*

*>> Christoph
*

*>>
*

*>>
*

*>>
*

*>>
*

*>> leeznar schrieb:
*

*>>> Dear R-users:
*

*>>>
*

*>>> I am a new R-user and I have a question about lm
*

*>>> function. Here is my data.
*

*>>> a<-c(1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,14)
*

*>>> b<-c(1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2)
*

*>>> c<-c(2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2)
*

*>>> d<-c(2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1)
*

*>>> e<-c(1739,1633,1481,1837,1780,2073,1374,1629,1555,1385,1756,1522,1566,1643,1939,1615,1475,1759,1388,1483,1127,1682,1542,1247,1235,1605,1598,1718
*

*>>> )
*

*>>> Data<-data.frame(subject=as.factor(a),
*

*>>> drug=as.factor(b), period=as.factor(c),
*

*>>> sequence=as.factor(d), Max=e)
*

*>>>
*

*>>> lm3<- lm(Max ~subject*sequence + sequence + period +
*

*>>> drug, data=Data)
*

*>>> print(lm3)
*

*>>> anova(lm3)
*

*>>>
*

*>>> When I use lm to fit the data, there are some problems
*

*>>> in "subject*sequence". I have use GLM in SPSS to
*

*>>> fit the same data, and it seems there is no problem.
*

*>>>
*

*>>> I don't know where my problem is. How can I get the
*

*>>> same result with SPSS? How can I do?
*

*>>>
*

*>>> Best regards,
*

*>>> Hsin-Ya Lee
*

*>>>
*

*>>>
*

*>>>
*

*>>>
*

*>>>
*

*>>> ______________________________________________________________________________________________________
*

*>>> [[elided Yahoo spam]]
*

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*

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*

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*

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*

*>>>
*

*>>>
*

*>>>
*

*>>> ------------------------------------------------------------------------
*

*>>>
*

*>>> ______________________________________________
*

*>>> R-help_at_r-project.org mailing list
*

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*

*>>> PLEASE do read the posting guide
*

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*

*>> ______________________________________________
*

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*

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*>>
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*>>
*

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. Received on Thu 17 Jul 2008 - 13:22:41 GMT

Date: Thu, 17 Jul 2008 15:14:07 +0200

Dear Hsin-Ya,

The problem here is that subject is a factor with 14 levels, and sequence again is a factor with 2 levels; so the subject:sequence interaction already uses up another (13*1)=13 d.f.; given that there are only 28 replicates, it is not surprising that there are no residual degrees of freedom left!

What do you intend to test with your model? Maybe I can be of help to solve the problem

Best wishes

Christoph

leeznar_at_yahoo.com.tw schrieb:

> Dear Dr. Christoph: > > Thanks for your reply. I am sure that I use the same data to run GLM with SPSS, but SPSS seems work!! > I also try your suggestion. I change the sequence data. > a<-c(1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,14) > b<-c(1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2) > c<-c(2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2) > d<-c(2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1) > d<-c(1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1,1,2,2,1) > e<-c(1739,1633,1481,1837,1780,2073,1374,1629,1555,1385,1756,1522,1566,1643,1939, > 1615,1475,1759,1388,1483,1127,1682,1542,1247,1235,1605,1598,1718 ) > KK<-data.frame(subject=as.factor(a), drug=as.factor(b), period=as.factor(c), sequence=as.factor(d), Max=e) > lm3<- lm(Max ~ subject*sequence + period + drug+sequence , data=KK) > print(lm3) > anova(lm3) > > However, it can not work!! > So, where is the problems? Do I misunderstand what you mean? > > > Best regards, > Hsin-Ya > > > Dr. Christoph Scherber wrote:

>> Dear Hsin-Ya Lee,

> Quoted from: > http://www.nabble.com/Problems-with-lm%28%29-tp17999900p18000246.html > > > . > ______________________________________________R-help_at_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. Received on Thu 17 Jul 2008 - 13:22:41 GMT

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