Thanks for your advice! I found another method to solve my problem (on page 20 of the manual =) ). Here's my code
# Set n and m to whatever you want n = 25 m = 10 # Build a random vector (here with exponential distribution) with lenght of n*m x = rexp(n*m,1) # Set up a factor in order to group x into pieces each of size ten y = factor( rep(1:n, each = m) ) # tapply will apply mean to each group.. result = tapply(x,y,mean) -- View this message in context: http://r.789695.n4.nabble.com/calculating-the-mean-of-a-random-matrix-by-row-and-some-general-questions-tp3678964p3679186.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
