Hi Anthony,

Perhaps

?rowSums
?apply
?aggregate
?ave

Here is an example:

set.seed(123)
X <- matrix(rnorm(40), ncol = 4)
colnames(X) <- c('x1','x2','x3','x4')
X

x <- rowSums(X)
x

cbind(X, x)


HTH,
Jorge


On Sat, Mar 20, 2010 at 4:02 PM, Anthony Lopez <> wrote:

> hello,
>
> I am new to R (convert from Stata) and I am wondering if there is an R
> command/function for generating a summated scale from, for example, four
> separate variables in a data set.  In other words, I want to transform the
> variables x1, x2, x3, and x4 (which have high inter-item reliability) into
> one new summated variable x'.  Can't seem to find it in the psy or psych
> package ...
>
> Thanks for any suggestions!
>
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