[R] Calculate Mean of Column Vectors?

[Thomas Hopper]

Hello,

I've got an array defined as y <- rnorm(3000), dim(y) <- c(3, 1000).

I'd like to produce a 1000-element vector z that is the mean of the 
corresponding elements of y (like z[1,1] <- mean(y[1,1], y[2,1], 
y[3,1])), but being new to R, I'm not sure how to do this for all 
elements at once (or, at least, simply). Any help is appreciated.

Thanks,

Tom