Dear Dominik, There's not enough information here to answer your question: You don't show the commands you used, nor the output that was produced, and you don't share your data. A good guess, however, is that there is only one level of the factor, perhaps after missing data are removed, and so it's not possible to compute a biserial correlation.
By the way, if the dichotomous factor is really nominal, then it doesn't make sense to compute a biserial correlation, which assumes that there's a latent continuous and normally distributed variable that has been dichotomized at an unknown threshold. Best, John ----------------------------- John Fox, Professor McMaster University Hamilton, Ontario Canada L8S 4M4 web: socserv.mcmaster.ca/jfox ________________________________________ From: R-help [r-help-boun...@r-project.org] on behalf of Dominik Maiori [d.mai...@windowslive.com] Sent: April 16, 2016 5:39 AM To: r-help@r-project.org Subject: [R] Problem: No p-value for a point-baserial correlation with R Dear community I'm pretty new to R and I'm trying to do a Point-baserial correlation for a nominal dichotomous variable with a interval scaled variable. It works fine, but the output just shows me the correlation and nothing else (p-Value would be important). I tried it with the following codes: - biseral.cor() - cor.biseral() - I also tried a polyserial() I've found on this question page: http://stackoverflow.com/questions/35880910/point-biserial-and-p-value Problem: It's not working (telling me y has fewer than 2 levels) and it would also be for a ordinal dichotomous variable, but I only have a nominal dichotomous variable. In the forum if found following Syntax that I've tried out: https://stat.ethz.ch/pipermail/r-help/2003-April/031852.html It seams to work because I don't get any error messages but I'm not getting an output either. I'm really thankful for every help I could get on this topic or tips where I can find out and learn how to find a correlation with a p-value in R for a nominal dichotomous and an interval scaled variable. Thanks in advance and have a nice weekend! [[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. ______________________________________________ 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.
