[R] Calculating Mean

Rui Barradas ruipbarradas at sapo.pt
Mon Jun 3 12:20:16 CEST 2013


Like Ivan said, you should give us a data example, the best way is to do 
it is to paste the output of ?dput in a post. If your data frame is 
named 'dat' use the following.

dput(head(dat, 50))  # paste the output of this in a post

As for the question, here is an example using ?aggregate, with fake data.

dat <- data.frame(X = rnorm(100), A = sample(8, 100, TRUE))

aggregate(X ~ A, data = dat, FUN = mean)

Hope this helps,

Rui Barradas

Em 03-06-2013 10:15, Laura Thomas escreveu:
> Hi All,
> Sorry about this quite basic, but I am very new to R.
> I have a data file which has a dependent variable (reaction time) and a couple of independent variables, one of which is coded 1-8; I want to calculate the reaction time for each of the 8 codes of the independent variable.
> Thanks for any help,
> Laura
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

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