[R] comparing distributions

I have data sets from three different sites. None of the data sets are normally distributed and can not be log-transformed to a normal distribution. I would like to compare the data sets to see if any of the sites are similar to each other, and would like something more powerful than a non-parametr

[R] correlation between a discrete variable and a continuous variable

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 wa

[R] correlation

What test do I use to determine if there is a correlation between a discrete variable and a continuous variable? For example - I have water quality ratings for streams (excellent, good, fair, poor) and a corresponding nitrogen concentration for each rating. I want to know if the the ratings correl