Dear developers of R-project, I have such data height of male persons 181, 178, 182, 160, 187, 193, 184, 184, 175, 178, 184, 184, 174, 185, 175 height of female persons 164, 165, 160, 174, 167, 161, 164, 165, 169, 175, 165, 155, 172, 164, 172, 166, 160, 159, 158, 173 I want to determine if height is dependent on gender, and I need to find, as I understand, point biserial correlation. I had tried to use package "ltm", and obtained coefficient which is about 0.74. I also had tried to calculate it manually (with some MS Excel help for simple calculations), using equation given in Internet (e.g., in Wikipedia; this equation is also given in some copy-books) and obtained coefficient is about 0.77. "ltm" provides somewhat other equation with pi-numbers. So, the questions are following: 1). Do exist packages in R-project, except of "polycor" and "ltm", which provide calculation of point biserial correlation? 1a). Why "ltm" use "non-traditional" equation for bisserial coefficient? Which is significance of this difference? 2). Can I also calculate significance of the biserial correlation coefficient (p < ???; using, probably, t-test) by means of R-project?
Thank You for advance. With regard, Dmitry Gospodaryov. ______________________________________________ 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.
