[R] how to run r biotools boxM terst on multiple groups?

Luigi Marongiu m@rong|u@|u|g| @end|ng |rom gm@||@com
Tue Jan 4 16:32:01 CET 2022


thanks, this is essentially merging bin and species into a single
variable. I was more interested in knowing if boxM can run on multiple
classes directly...

On Tue, Jan 4, 2022 at 12:34 PM PIKAL Petr <petr.pikal using precheza.cz> wrote:
>
> Hi.
>
> Not sure if statistically correct but what about
>
> iris$int<- interaction(iris$bin, iris$Species)
> boxM(iris[,1:4], iris[,7])
>
> Cheers
> Petr
>
> > -----Original Message-----
> > From: R-help <r-help-bounces using r-project.org> On Behalf Of Luigi Marongiu
> > Sent: Tuesday, January 4, 2022 11:56 AM
> > To: r-help <r-help using r-project.org>
> > Subject: [R] how to run r biotools boxM terst on multiple groups?
> >
> > I have a data frame containing a half dozen continuous measurements and
> > over a dozen ordinal variables (such as, death, fever, symptoms etc).
> > I would like to run a box matrix test and I am using biotools' boxM, but
> it
> > allows to run only one ordinal group at the time. For instance:
> > ```
> > >data(iris)
> > >boxM(iris[,1:4], iris[,5])
> >
> > Box's M-test for Homogeneity of Covariance Matrices
> >
> > data:  iris[, 1:4]
> > Chi-Sq (approx.) = 140.94, df = 20, p-value < 2.2e-16
> >
> > >bins <- c(1,2); iris$bin <- findInterval(iris$Petal.Width, bins)
> > >iris$bin = factor(iris$bin) boxM(iris[,1:4], iris[,6])
> >
> > Box's M-test for Homogeneity of Covariance Matrices
> >
> > data:  iris[, 1:4]
> > Chi-Sq (approx.) = 140.94, df = 20, p-value < 2.2e-16
> >
> > >boxM(iris[,1:4], iris[,5:6])
> > Error in boxM(iris[, 1:4], iris[, 5:6]) : incompatible dimensions!
> > ```
> > Is there a way to check for equality of variance-covariance on multiple
> groups
> > simultaneously?
> > Thanks
> >
> > ______________________________________________
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-- 
Best regards,
Luigi



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