> > Kumar and Jim, > The phi coefficient is identical to the Pearson coefficient in the case of a > 2 x 2 data set. > > As it says in the help file for phi: > > "Since the phi coefficient is just a Pearson correlation applied to > dichotomous data, to find a matrix of phis from a data set involves just > finding the correlations using cor or lowerCor or corr.test.” > > So, you can do a cor(df) and you do not need the phi(df) > > If you want the tetrachoric (which estimates what a Pearson would be if you > had not artificially dichotomized the data) try tetrachoric(df) > > Bill >
> > > >> On Apr 21, 2015, at 3:34 PM, Kumar Mainali <kpmain...@gmail.com> wrote: >> >> I want to calculate phi coefficient for every pair of the columns. Is there >> a way to generate a matrix like a correlation matrix? I know cor function >> in the case below gives same answer as phi coefficient. >> >> x <- sample(c(0,1), 10, replace=TRUE) >> y <- sample(c(0,1), 10, replace=TRUE) >> z <- sample(c(0,1), 10, replace=TRUE) >> df <- data.frame(x,y,z) >> cor(df) >> library(psych) >> phi(df) >> >> Thank you, >> Kumar Mainali >> Postdoctoral Associate >> Department of Biology >> University of Maryland >> ᐧ >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. > > William Revelle > http://personality-project.org/revelle.html > Professor http://personality-project.org > Department of Psychology http://www.wcas.northwestern.edu/psych/ > Northwestern University http://www.northwestern.edu/ > Use R for psychology http://personality-project.org/r > It is 3 minutes to midnight http://www.thebulletin.org > > > > > > William Revelle http://personality-project.org/revelle.html Professor http://personality-project.org Department of Psychology http://www.wcas.northwestern.edu/psych/ Northwestern University http://www.northwestern.edu/ Use R for psychology http://personality-project.org/r It is 3 minutes to midnight http://www.thebulletin.org ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
