[R] car/MANOVA question

2012-03-19 Thread Ranjan Maitra
Dear colleagues,

I had a question wrt the car package. How do I evaluate whether a
simpler multivariate regression model is adequate?

For instance, I do the following:

ami - read.table(file =
http://www.public.iastate.edu/~maitra/stat501/datasets/amitriptyline.dat;,
col.names=c(TCAD, drug, gender, antidepressant,PR, dBP,
QRS))

ami$gender - as.factor(ami$gender)
ami$TCAD - ami$TCAD/1000
ami$drug - ami$drug/1000


library(car)

fit.lm - lm(cbind(TCAD, drug) ~ gender + antidepressant + PR + dBP +
QRS, data = ami)

fit.manova - Manova(fit.lm)

fit1.lm - update(fit.lm, .~ . - PR - dBP - QRS)

fit1.manova - Manova(fit1.lm)



Is there an easy way to find out whether the reduced model is adequate?

I am thinking of something similar to the anova() function, I guess?

Many thanks and best wishes,
Ranjan

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Re: [R] car/MANOVA question

2012-03-19 Thread John Fox
Dear Ranjan,

As you no doubt noticed, the Manova() function in the car package, or the 
Anova() function for which Manova() is an alias, produces type II or III tests 
for a multivariate linear model. To compare two nested multivariate linear 
models, as you wish to do, you can use the standard R anova() function -- see 
?anova.mlm.

I hope this helps,
 John


John Fox
Sen. William McMaster Prof. of Social Statistics
Department of Sociology
McMaster University
Hamilton, Ontario, Canada
http://socserv.mcmaster.ca/jfox/

On Mon, 19 Mar 2012 12:31:48 -0500
 Ranjan Maitra mai...@iastate.edu wrote:
 Dear colleagues,
 
 I had a question wrt the car package. How do I evaluate whether a
 simpler multivariate regression model is adequate?
 
 For instance, I do the following:
 
 ami - read.table(file =
 http://www.public.iastate.edu/~maitra/stat501/datasets/amitriptyline.dat;,
 col.names=c(TCAD, drug, gender, antidepressant,PR, dBP,
 QRS))
 
 ami$gender - as.factor(ami$gender)
 ami$TCAD - ami$TCAD/1000
 ami$drug - ami$drug/1000
 
 
 library(car)
 
 fit.lm - lm(cbind(TCAD, drug) ~ gender + antidepressant + PR + dBP +
 QRS, data = ami)
 
 fit.manova - Manova(fit.lm)
 
 fit1.lm - update(fit.lm, .~ . - PR - dBP - QRS)
 
 fit1.manova - Manova(fit1.lm)
 
 
 
 Is there an easy way to find out whether the reduced model is adequate?
 
 I am thinking of something similar to the anova() function, I guess?
 
 Many thanks and best wishes,
 Ranjan
 
 __
 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.

__
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.