Colleagues, The RVAideMemoire package has a pairwise variance test which one can use to identify variance differences between group levels. Using the example from this package, pairwise.var.test(InsectSprays$count,InsectSprays$spray), we get this output: ??? Pairwise comparisons using F tests to compare two variances data:? InsectSprays$count and InsectSprays$spray ?? A????? ????????B????? ?????? C????? ?????? D????? ????? E ??? B 0.7464 ????-?????????????? -????? ?? ???? -????? ????????-??? ? C 0.0187 ????0.0358???? -????? -?????? -??? ? D 0.0865 ????0.1502 ????0.5131 ????-???????????? -??? ? E 0.0122???? 0.0173 ????0.7185 ????0.3240??? -??? ? F 0.4693 ????0.3240 ????0.0050 ????0.0173 ????0.0029 P value adjustment method: fdr Is there a way to graph the pairwise variance differences so that users can easily identify the statistically significant variance differences between group levels? I can do this using Minitab but I'd prefer using R for this. Thomas Subia
Hi Thomas,
I have assumed the format of your p-value matrix. This may require
some adjustment.
A B C D E F
A 1 0.7464 0.0187 0.0865 0.0122 0.4693
B 0.7464 1 0.0358 0.1502 0.0173 0.3240
C 0.0187 0.0358 1 0.5131 0.7185 0.0050
D 0.0865 0.1502 0.5131 1 0.3240 0.0173
E 0.0122 0.0173 0.7185 0.3240 1 0.0029
F 0.4693 0.3240 0.0050 0.0173 0.0029 1
pvar.mat<-as.matrix(read.table(text "1 0.7464 0.0187
0.0865 0.0122 0.4693
0.7464 1 0.0358 0.1502 0.0173 0.3240
0.0187 0.0358 1 0.5131 0.7185 0.0050
0.0865 0.1502 0.5131 1 0.3240 0.0173
0.0122 0.0173 0.7185 0.3240 1 0.0029
0.4693 0.3240 0.0050 0.0173 0.0029 1",
stringsAsFactors=FALSE))
rownames(pvar.mat)<-colnames(pvar.mat)<-LETTERS[1:6]
pvar.col<-matrix(NA,nrow=6,ncol=6)
pvar.col[pvar.mat < 1]<-"red"
pvar.col[pvar.mat < 0.05]<-"orange"
pvar.col[pvar.mat < 0.01]<-"green"
library(plotrix)
par(mar=c(6,4,4,2))
color2D.matplot(pvar.mat,cellcolors=pvar.col,
main="P-values for matrix",axes=FALSE)
axis(1,at=seq(0.5,5.5,by=1),labels=LETTERS[1:6])
axis(2,at=seq(0.5,5.5,by=1),labels=rev(LETTERS[1:6]))
color.legend(0,-1.3,2.5,-0.7,c("NA","NS","<0.05","<0.01"),
rect.col=c(NA,"red","orange","green"))
Jim
On Mon, Oct 31, 2022 at 6:34 AM Thomas Subia via R-help
<r-help at r-project.org> wrote:>
> Colleagues,
>
> The RVAideMemoire package has a pairwise variance test which one can use to
identify variance differences between group levels.
>
> Using the example from this package,
pairwise.var.test(InsectSprays$count,InsectSprays$spray), we get this output:
>
> Pairwise comparisons using F tests to compare two variances
>
> data: InsectSprays$count and InsectSprays$spray
>
> A B C D E
> B 0.7464 - - - -
> C 0.0187 0.0358 - - -
> D 0.0865 0.1502 0.5131 - -
> E 0.0122 0.0173 0.7185 0.3240 -
> F 0.4693 0.3240 0.0050 0.0173 0.0029
>
> P value adjustment method: fdr
>
> Is there a way to graph the pairwise variance differences so that users can
easily identify the statistically significant variance differences between group
levels?
>
> I can do this using Minitab but I'd prefer using R for this.
>
> Thomas Subia
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
Hard to know what you want. You may wish to take a look here for ideas: https://r-graph-gallery.com/ Cheers, Bert On Sun, Oct 30, 2022 at 12:34 PM Thomas Subia via R-help < r-help at r-project.org> wrote:> Colleagues, > > The RVAideMemoire package has a pairwise variance test which one can use > to identify variance differences between group levels. > > Using the example from this package, > pairwise.var.test(InsectSprays$count,InsectSprays$spray), we get this > output: > > Pairwise comparisons using F tests to compare two variances > > data: InsectSprays$count and InsectSprays$spray > > A B C D E > B 0.7464 - - - - > C 0.0187 0.0358 - - - > D 0.0865 0.1502 0.5131 - - > E 0.0122 0.0173 0.7185 0.3240 - > F 0.4693 0.3240 0.0050 0.0173 0.0029 > > P value adjustment method: fdr > > Is there a way to graph the pairwise variance differences so that users > can easily identify the statistically significant variance differences > between group levels? > > I can do this using Minitab but I'd prefer using R for this. > > Thomas Subia > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. >[[alternative HTML version deleted]]