[R] mean

[Dimitris Rizopoulos]

sorry, that should be

tapply(x2, x1, mean)


Best,
Dimitris

Dimitris Rizopoulos wrote:
> 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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