With the following data in data.frame: subject QM emotion yi s1 75.1017 neutral -75.928276 s2 -47.3512 neutral -178.295990 s3 -68.9016 neutral -134.753906 s1 17.2099 negative -104.168312 s2 -53.1114 negative -182.373474 s3 -33.0322 negative -137.420410
I can obtain the average between the two emotions with mydata <- read.table('clipboard', header=TRUE) aggregate(mydata[,c('yi', 'QM')], by=list(subject=mydata$subject), mean) My question is, what is a nice way to get the difference between the two emotions? Thanks, Gang ______________________________________________ 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.