Hi, I am trying to test a mediation hypothesis using coefficients from logistic regression analyses (x, m, and y are all dichotomous). I am running a test of significance using MacKinnon and Dwyer's adaptation of Sobel's test (i.e., correcting for different scales of coefficients in cases of a dichotomous outcome).
In order to make this correction I need to compute the covariance between x and m. I have searched various R packages and the R-help page archive and cannot find a way to do this in R. Does anyone know how to compute the covariance between two dichotomous variables in R? It seems like there should be a very simple answer to this question, but I cannot find it. Thanks in advance! Heather -- Heather Hensman Kettrey PhD Candidate Department of Sociology Vanderbilt University [[alternative HTML version deleted]] ______________________________________________ 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.