What test would you use to determine if a correlation exists between a discrete variable and a continuous variable?
For example, I have a rating for stream water quality (excellent, good, fair, poor) and a corresponding nitrogen concentration. I want to see if there is a correlation between the water quality rating and the concentration of nitrogen in the stream. Help? ______________________________________________ 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.
