Your problem would be a lot easier if you coded the location in one variable instead of three variables. Then you could calculate the means with one line of code:
by(results$q1, results$location, mean) With your dataset you could use by(results$London, results$location, mean) by(results$Rome, results$location, mean) by(results$Vienna, results$location, mean) see ?by for more information And take a good look at your code. You take a subset from results and the assign it to results. This means that you replace the original results dataframe with a subset of it. As you take the subset for the next city, you won't take a subset from the original dataset but for the previous subset! Cheers, Thierry ------------------------------------------------------------------------ ---- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Reseach Institute for Nature and Forest Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and quality assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 [EMAIL PROTECTED] www.inbo.be -----Oorspronkelijk bericht----- Van: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Namens Peter Wolkerstorfer - CURE Verzonden: maandag 25 september 2006 13:51 Aan: [email protected] Onderwerp: [R] Beginner question: select cases Hello all, I hope i chose the right list as my question is a beginner-question. I have a data set with 3 colums "London", "Rome" and "Vienna" - the location is presented through a 1 like this: London Rome Vienna q1 0 0 1 4 0 1 0 2 1 0 0 3 .... .... .... I just want to calculate the means of a variable q1. I tried following script: # calculate the mean of all locations results <- subset(results, subset== 1 ) mean(results$q1) # calculate the mean of London results <- subset(results, subset== 1 , select=c(London)) mean(results$q1) # calculate the mean of Rome results <- subset(results, subset== 1 , select=c(Rome)) mean(results$q1) # calcualate the mean of Vienna results <- subset(results, subset== 1 , select=c(Vienna)) mean(results$q1) As all results are 1.68 and there is defenitely a difference in the three locations I wonder whats going on. I get confused as the Rcmdr asks me to overwrite things and there is no "just filter" option. Any help would be apprechiated. Thank you in advance. Regards Peter ___CURE - Center for Usability Research & Engineering___ Peter Wolkerstorfer Usability Engineer Hauffgasse 3-5, 1110 Wien, Austria [Tel] +43.1.743 54 51.46 [Fax] +43.1.743 54 51.30 [Mail] [EMAIL PROTECTED] [Web] http://www.cure.at ______________________________________________ [email protected] 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. ______________________________________________ [email protected] 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.
