Hi, I am new to R and have not had the most exposure to statistics. I have a dataset of percentage cover (so 0-100) for certain species in 3 different shore zones (High, mid and low). The data was recorded for different protected areas as well (17 of them) and my number of obs is large (3358). I'm obviously interested in the difference in percentage cover of species between shore zones as well as between protected areas. The problem is that my data contains loads of zeros and I haven't dealt yet in statistics with how to manipulate the data so as to perform robust tests on it. I previously used Kruskal-Wallis ANOVAs to look at cover differences in shore zone but I am worried that it is inappropriate because of the large sample size that I have and because my variances are not equal.
I've read a bit about using a zero-inflated negative binomial regression to fit to my data, but I'm not sure if that will work because it is for count data. I would very much appreciate it if someone could point me in the correct direction wrt a transformation that may help or an appropriate model to fit or test to use. I've searched quite a bit but I'm a out of my depth. PS sorry if I sound like a halfwit Thanks a lot Ben [[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.