On Apr 2, 2014, at 8:09 AM, Elizabeth Caron-Gamache <babeth_...@icloud.com> wrote:
> Hi, > > I search on your website for a definition of the CORDIF test, but it wasn’t > successful. I’m analyzing an article that use that test and it’s not really > documented on the net. The article refers to your website, so I pretend that > you will be able to give me a brief explanation of this test. Here is the > cote that talk about this test in my article : > > ‘' To compare these regressions and to see which—either body height or LLL—is > best related to performance (Pearson correlation coefficients comparison), a > CORDIF test (R software [www.r-project.org], multilevel package, ver- sion > 2.12.1) was performed. > > Does it use parametric or non-parametric values ? > Is it a test to compare 2 groups only or it can be used for a comparison of > more than two groups ? > Why is it so hard to find information on that test on the net ? > > Thanks for your time > Have a nice day > > Elizabeth Caron > Physical therapist student, Laval University, Qc, Canada Thanks for including the citation, which indicates that the CORDIF test is part of the 'multilevel' package, which is on CRAN: http://cran.r-project.org/web/packages/multilevel/index.html The reason that it is likely difficult is that 'cordif' is an abbreviation for "correlation difference", not the proper name for a test. If you review the provided documentation for the package: http://cran.r-project.org/web/packages/multilevel/multilevel.pdf you will see that there is a description of the cordif() function and a reference given: Cohen, J. & Cohen, P. (1983). Applied multiple regression/correlation analysis for the behavioral sciences (2nd Ed.). Hillsdale, NJ: Lawrence Erlbaum Associates. I would review the package documentation and reference and if you have further questions, contact the authors of the paper. Regards, Marc Schwartz ______________________________________________ R-help@r-project.org 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.
