[R] Point biserial correlation => Is there any specific command or could I just use cor.test?

[John Fox]

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 <info at 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
> info at aghmed.fsnet.co.uk
> http://www.aghmed.fsnet.co.uk/home.html
> 
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