I have water chemistry data with censored values (i.e., those less than reporting levels) in a data frame with a narrow (i.e., database table) format. The structure is:
$ site : Factor w/ 64 levels "D-1","D-2","D-3",..: 1 1 1 1 1 1 1 1 ... $ sampdate: Date, format: "2007-12-12" "2007-12-12" ... $ preeq0 : logi TRUE TRUE TRUE TRUE TRUE TRUE ... $ param : Factor w/ 37 levels "Ag","Al","Alk_tot",..: 1 2 8 17 3 4 9 ... $ quant : num 0.005 0.106 1 231 231 0.011 0.001 0.002 0.001 100 ... $ ceneq1 : logi TRUE FALSE TRUE FALSE FALSE FALSE ... $ floor : num 0 0.106 0 231 231 0.011 0 0 0 100 ... $ ceiling : num 0.005 0.106 1 231 231 0.011 0.001 0.002 0.001 100 ... The logical 'preeq0' separates sampdate into two groups; 'ceneq1' indicates censored/uncensored values; 'floor' and 'ceiling' are the minima and maxima for censored values. The NADA package methods will be used, but I have not found information on whether this format or the wide (i.e., spreadsheet) format should be used. The NADA.pdf document doesn't tell me; at least, I haven't found the answer there. I can apply reshape2 to melt and re-cast the data in wide format if that's what is appropriate. Please provide a pointer to documents I can read for an answer to this and related questions. Rich ______________________________________________ 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.
