Martin Pl?derl wrote:> Hello!
>
> For comparing two non-normally distributed samples, Leech (2002) suggested
> to report nonparametric effect size indices, such as Vargha &
Delaney's A or
> Cliff's d. I tried to search the R-sites, but could not find related
> procedures or packages that include nonparametric effect sizes.
> Thank you for your help!
>
> Citation: Leech (2002). A call for greater use of nonparametric statistics.
> Paper presented at the Annual Meeting of the Mid-South Educational Research
> Association, Chattanooga, TN, November 6-8.
Based on the description of Cliff's d in
http://www.florida-air.org/romano06.pdf, you could do something like the
following:
g1 <- c(1,1,2,2,2,3,3,3,4,5)
g2 <- c(1,2,3,4,4,5)
# Dominance matrix
sign(outer(g1, g2, FUN="-"))
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 0 -1 -1 -1 -1 -1
[2,] 0 -1 -1 -1 -1 -1
[3,] 1 0 -1 -1 -1 -1
[4,] 1 0 -1 -1 -1 -1
[5,] 1 0 -1 -1 -1 -1
[6,] 1 1 0 -1 -1 -1
[7,] 1 1 0 -1 -1 -1
[8,] 1 1 0 -1 -1 -1
[9,] 1 1 1 0 0 -1
[10,] 1 1 1 1 1 0
mean(rowMeans(sign(outer(g1, g2, FUN="-"))))
[1] -0.25
If you can point us to a description of Vargha & Delaney's A, someone
can likely suggest a way of obtaining that too.
> Regards,
>
> Martin Pl?derl PhD
> Suicide Prevention Research Program, Institute of Public Health
> Paracelsus Private Medical University
> Dept. of Suicide Prevention, University Clinic of Psychiatry and
> Psychotherapy
> Christian - Doppler - Klinik
> Ignaz Harrerstrasse 79
> A-5020 Salzburg
> AUSTRIA
> Phone: +43-662-4483-4345
> Fax: +43-662-4483-4344
> E-mail: M.Ploederl at salk.at
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> 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.
--
Chuck Cleland, Ph.D.
NDRI, Inc.
71 West 23rd Street, 8th floor
New York, NY 10010
tel: (212) 845-4495 (Tu, Th)
tel: (732) 512-0171 (M, W, F)
fax: (917) 438-0894