Hello, I cannot figure out how to use "tapply" to compute the correlation matrix in the variable "x" between the states? The data is in long format, e.g.:
state,year,x Alabama,2001,0.45 Alabama,2002,0.47 Alabama,2003,0.48 Alabama,2004,0.44 Arizona,2001,0.34 Arizona,2002,0.32 Arizona,2003,0.38 Arizona,2004,0.36 Thank you in advance for your help, Serguei Kaniovski ______________________________________________ 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.
