[R] Mean according to the combination of two factors

[Rui Barradas]

Hello,

Try the following.

# make up some data
dat <- data.frame(values = rnorm(100), experiment = sample(10, 100, 
TRUE), composite = sample(17, 100, TRUE))
aggregate(values ~ experiment + composite, data = dat, FUN = mean)


Hope this helps,

Rui Barradas
Em 11-01-2013 23:26, li li escreveu:
> Dear all,
>     I have a data frame where there are three variables: values, experiment,
> composite.
> Values are numerical values. There are 10 levels for the experiment. Within
> each level of experiment,
> there are 17 levels of composite.
>    I want to find mean for each combination of levels of the experiment and
> the levels of composite.
>    Can anyone give some help here.
>    Thank you, Hanna
>
> 	[[alternative HTML version deleted]]
>
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