Dear Michael and Cadu, Sorry -- I missed the original question.
The polycor package has functions for polyserial and polychoric correlations; biserial and tetrachoric correlations are special cases for dichotomous variables. The point biserial correlation is just the Pearson correlation between a numeric variable and a dummy variable. Best, John ------------------------------------------------ John Fox Sen. William McMaster Prof. of Social Statistics Department of Sociology McMaster University Hamilton, Ontario, Canada http://socserv.mcmaster.ca/jfox/ On Sat, 21 Jan 2012 13:31:48 +0000 Michael Dewey <i...@aghmed.fsnet.co.uk> wrote: > At 13:15 20/01/2012, Cadu wrote: > >Hello, > > > > > > > >I found in the forum two threads about point biserial correlation. One of > >them (1) mentioned "a point-biserial correlation is just a Pearson > >correlation where one of the variables is dichotomous. Thus, the command > >is just the normal cor function". The other (2) mentioned "Professor Fox's > >package polycor" as a way to calculate point biserial correlation? > > polycor calculate polyserial correlations. I am confident if John Fox had > meant point polyserial he would have written thus. You can always check what > it is doing by downloading the source - R is open source. > > > > > > >HELP: I am a little confused about what to do. I just need to obtain the > >correlation index and p-value. Could I just use cor.test? Or is necessary to > >use other command or even "Professor Fox's package polycor"? > > > > > > > >Thanks in advance, > > > >Cadu > > > > > > > >1. http://r.789695.n4.nabble.com/Point-biserial-correlation-td862060.html > > > >2. > >http://r.789695.n4.nabble.com/Correlation-dichotomous-factor-continous-numer > >ical-and-ordered-factor-td865214.html#a865215 > > > > > > > > > > [[alternative HTML version deleted]] > > Michael Dewey > i...@aghmed.fsnet.co.uk > http://www.aghmed.fsnet.co.uk/home.html > > ______________________________________________ > 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 ______________________________________________ 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.
