Ah, I believe I constructed my *.csv wrong in that I only had 1 observation within groups whereas I needed at least 2.
Originally I had: Year Depth Biomass1 Biomass2 1999 10 14.3 14.7 1999 15 14.7 15.6 etc. but I switched this to: Year Depth Biomass 1999 10 14.3 1999 10 14.7 1999 15 15.1 1999 15 15.6 I believe this may be the appropriate way to collapse my biomass data in order to perform a 2-way anova. If not feel free comment and thanks for the help. -- View this message in context: http://old.nabble.com/Simple-2-Way-Anova-issue-in-R-tp26258684p26259649.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.