HI,
I am trying to figure out an efficient way to calculate group means and
associate each entry with it. I made up an example:
A = rep(rep(0:1,each=2),3)
B = rep(rep(0:1,4),3)
C = rep(rep(c(0,0,1,1),2),3)
X =cbind(rnorm(24,0,1),runif(24,0,1),A,B,C)
A B C
[1,] -1.92926469 0.32213127 0 0 0
[2,] -0.83935617 0.77794096 0 1 0
[3,] -1.27799751 0.26276934 1 0 1
Suppose I want to compute a weighted mean of X[,1] by for each group, which
is defined by unique vector (A,B,C) with weights are X[,2]. And then add a
column for the weighted group mean. How can I do this ? My matrix is fairly
large (few thousands) but, luckily, I have only a few factors (<10).
Thanks a lot,
Young.
[[alternative HTML version deleted]]
______________________________________________
R-help@stat.math.ethz.ch 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.
