Page 1 of 1
Friedman & Paired Comparisons (Durbin-Conover)
Posted: Tue Jun 23, 2020 9:08 pm
by pstjacques
I am conducting Friedman non-parametric test, followed by pairwise comparisons (Durbin-Conover). I was wondering if the p-values reported in the table are already adjusted for multiple comparisons?
Re: Friedman & Paired Comparisons (Durbin-Conover)
Posted: Wed Jun 24, 2020 2:09 pm
by MAgojam
Hi, @pstjacques.
The p values shown in the table are obtained as:
P value adjustment method: none
Take a look at the attached screenshot, where I use the Rj module and this little r script.
Code: Select all
library(PMCMR)
options(digits=5)
y <- data.matrix(data[1:6])
friedman.test(y)
# P value adjustment method: none
posthoc.friedman.conover.test(y, p.adj="none")
# P value adjustment method: bonferroni
posthoc.friedman.conover.test(y, p.adj="bonferroni")
- ScreenShot.png (105.26 KiB) Viewed 13636 times
Cheers,
Maurizio
Re: Friedman & Paired Comparisons (Durbin-Conover)
Posted: Wed Jun 24, 2020 4:36 pm
by pstjacques
Thanks very much for your response Maurizio! I'm a newbie to R, so it's helpful to see how you have used the Rj Module here.
Re: Friedman & Paired Comparisons (Durbin-Conover)
Posted: Wed Nov 03, 2021 12:27 pm
by jpmaroco
Dear Maurizio,
Can I jump into this?
Looking at the R script (in your print screen) one can see that the post-hoc test is `posthoc.friedman.conover.test(y=y, p.adjust="none")` from the PMCMR[/code] library. However, the test is named Durbin-Conover in jamovi. In he PMCMR there's also a Durbin test (for incomplete block designs that is the same as Friedman where the design is complete) and the Durbin post-hoc statistic in `posthoc.durbin.test` looks quite different from the Conover one.... So I am wondering why jamovi calls it Durbin-Conover (maybe it is because that both tests are the same when the design is complete?).
Warm regards,
João
Re: Friedman & Paired Comparisons (Durbin-Conover)
Posted: Fri Nov 05, 2021 9:10 pm
by MAgojam
jpmaroco wrote:So I am wondering why jamovi calls it Durbin-Conover (maybe it is because that both tests are the same when the design is complete?)João
Hi, João.
Sorry I'm late, but I lost you (I'm old).
We can resent in SLACK, because we are a bit distant in time from the post.
My intervention here was what was going on under Jamovi's hood.
In SLACK there are the 'J guys' who can motivate the choice.
Uma saudação calorosa.
Maurizio