R help - Jan 2018 - Letters group Games-Howell post hoc in R

Hello everybody,

I use the sweetpotato database included in R package:

data(sweetpotato) This dataset contains two variables: yield(continous
variable) and virus(factor variable).

Due to Levene test is significant I cannot assume homogeneity of variances
and I apply Welch test in R instead of one-way ANOVA followed by Tukey
posthoc.

Nevertheless, the problems come from when I apply posthoc test. In Tukey
posthoc test I use library(agricolae) and displays me the superscript
letters between virus groups. Therefore there are no problems.

Nevertheless, to perform Games-Howell posthoc, I use
library(userfriendlyscience) and I obtain Games-Howell output but it's
impossible for me to obtain a letter superscript comparison between virus
groups as it is obtained through library(agricolae).

The code used it was the following:

library(userfriendlyscience)

data(sweetpotato)

oneway<-oneway(sweetpotato$virus, y=sweetpotato$yield, posthoc
'games-howell')

oneway

I try with cld() importing previously library(multcompView) but doesn't
work.

Can somebody could helps me?

Thanks in advance,

David Bars.

Apologies if I missed any earlier replies - did you check
multcompLetters in package {multcompView}?
It allows you to get connecting letters reports (if that's what you are
after, I didn't check what exactly agricolae is providing here). May have to
add some manual steps to combine this with any data (means or whatever) you want
to report.
multcompLetters allows you to use p values or a logical (significant or not)
HTH, Michael
> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of David
Bars
> Cortina
> Sent: Dienstag, 16. Januar 2018 13:51
> To: R-help at r-project.org
> Subject: [R] Letters group Games-Howell post hoc in R
> 
> Hello everybody,
> 
> I use the sweetpotato database included in R package:
> 
> data(sweetpotato) This dataset contains two variables: yield(continous
> variable) and virus(factor variable).
> 
> Due to Levene test is significant I cannot assume homogeneity of variances
> and I apply Welch test in R instead of one-way ANOVA followed by Tukey
> posthoc.
> 
> Nevertheless, the problems come from when I apply posthoc test. In Tukey
> posthoc test I use library(agricolae) and displays me the superscript
letters
> between virus groups. Therefore there are no problems.
> 
> Nevertheless, to perform Games-Howell posthoc, I use
> library(userfriendlyscience) and I obtain Games-Howell output but it's
> impossible for me to obtain a letter superscript comparison between virus
> groups as it is obtained through library(agricolae).
> 
> The code used it was the following:
> 
> library(userfriendlyscience)
> 
> data(sweetpotato)
> 
> oneway<-oneway(sweetpotato$virus, y=sweetpotato$yield, posthoc >
'games-howell')
> 
> oneway
> 
> I try with cld() importing previously library(multcompView) but doesn't
work.
> 
> Can somebody could helps me?
> 
> Thanks in advance,
> 
> David Bars.
> 
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