[R] mean

Dimitris Rizopoulos d.rizopoulos at erasmusmc.nl
Mon Jun 8 14:15:56 CEST 2009


have a look at ?tapply(), e.g.,

x1 <- c(rep(1,6),rep(4,7),rep(6,10))
x2 <- rnorm(length(x1),6,1)

tapply(x1, x1, mean)


I hope it helps.

Best,
Dimitris


amor Gandhi wrote:
> Hi,
> 
> I have gote the following data
> 
> x1 <- c(rep(1,6),rep(4,7),rep(6,10))
> x2 <- rnorm(length(x1),6,1)
> data <- data.frame(x1,x2)
> 
> and I would like to compute the mean of the x2 for each individual of x1, i. e. x1=1,4 and 6?
> 
> Thank you very much in advance,
> 
> Amori
> 
> 
>       
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> 
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-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

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