[R] variable standardization in manova() call

[Sergio Fonda]

 thank you for your reply.
However, your remark was not so clear to me
so I attach a short script I tried to launch. The comparison between
results got from MANOVA() call with the non-standardized and
standardized version of the same data frame, convinced me that it is
not necessary to standardize data before calling MANOVA. The only
difference you get is in the residuals values, of course.
Could you kindly confirm my conclusion?

All the best,
Sergio Fonda
______________________
set.seed(1234)
# non- standardized series
x1 =  rnorm(n=10, mean=50, sd=11)
x2 =  rnorm(n=10, mean=93, sd=23)
x1 =  rnorm(n=10, mean=217, sd=52)
fact= rep(1:2,20)
glob1=data.frame(cbind(x1,x2,x3,fact))
fitta1=manova(cbind(x1,x2,x3)~fact, data=glob1)
fitta1.wilks=summary(fitta1, test="Wilks")
summary.aov(fitta1)

#after standardization
x.stand=scale(glob1[,-4])
glob2=data.frame(x.stand,fact)
fitta2=manova(cbind(x1,x2,x3)~fact, data=glob2)
fitta2.wilks=summary(fitta2, test="Wilks")
summary.aov(fitta2)

2013/11/4 Sergio Fonda <sergio.fonda99 at gmail.com>:
> Hi,
> I'm not able to get information about the following question:
>
> is the variables standardization a default option in manova() (stats package)?
> Or if you want to compare variables with different units or scales and
> rather different variances, you have to previously standardize the
> variables ?
>
> Thanks a lot for any help,
>
> Sergio Fonda
> www.unimore.it