I am having problems making a correlation/association between two variables by a factor.
In the case below, I need to know the correlation between R and Day at each frequency (a1-a5). Each frequency would have a corresponding correlation between R and day. I have found a lm function that is similar to what I need. lm(R~Day*Freq), but this wont apply to the cor function. Mind you, I have hundreds of these to with these same three columns, so if there is an association package, I would be interested in those too. I did research it, but it quickly went over my head, so I thought I would approach my problem this way. Data is below. Keith R<-c(1,8,3,6,7,2,3,7,2,3,3,4,3,7,3) Day<-c(1,1,1,1,1,2,2,2,2,2,3,3,3,3,3) Freq<-(a1,a2,a3,a4,a5,a1,a2,a3,a4,a5,a1,a2,a3,a4,a5,) M. Keith Cox, Ph.D. Principal MKConsulting 17415 Christine Ave. Juneau, AK 99801 U.S. 907.957.4606 [[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.