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! [[alternative HTML version deleted]]
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!
>
> [[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.
>
[[alternative HTML version deleted]]
Hi Anthony, Have a look at ?rowSums (if you just want to calculate the score) or ?score.items in the psych package (if you want to calculate alpha's, item-by-scale correlations etc.). -Ista On Sat, Mar 20, 2010 at 4:02 PM, Anthony Lopez <skytrek820 at gmail.com> 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! > > ? ? ? ?[[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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. >-- Ista Zahn Graduate student University of Rochester Department of Clinical and Social Psychology http://yourpsyche.org