I would suggest using summaryBy() library(doBy) # sample data with you specifications subject <- as.factor(rep(seq(13), each = 5)) state <- as.factor(sample(c(1:8), 65, replace = TRUE)) condition <- as.factor(sample(c(1:10), 65, replace = TRUE)) latency <- runif(65, min=750, max = 1100)
dat <- data.frame(subject, state, condition, latency) summaryBy(latency~subject+state+condition, data = dat, FUN = function(x) mean(x)) Regards, On Mon, Dec 23, 2013 at 6:31 AM, Laura Bethan Thomas [lbt1] <l...@aber.ac.uk > wrote: > > Hi All, > > > > Sorry for what I imagine is quite a basic question. I have been trying > to do is create latency averages for each state (1-8) for each participant > (n=13) in each condition (1-10). I'm not sure what function I would need, > or what the most efficient ay of calculating this would be. If you have any > help with that I would be very grateful. > > > > structure(list(subject = c(1L, 1L, 1L, 1L, 1L, 1L), conditionNo = c(1L, > > 1L, 1L, 1L, 1L, 1L), state = c(5L, 8L, 7L, 8L, 1L, 7L), latency = c(869L, > > 864L, 1004L, 801L, 611L, 679L)), .Names = c("subject", "conditionNo", > > "state", "latency"), row.names = 3:8, class = "data.frame") > > > > Thanks again, > > > > Laura > > ______________________________________________ > 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. > -- Charles Determan Integrated Biosciences PhD Candidate University of Minnesota [[alternative HTML version deleted]] ______________________________________________ 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.