[R] Integer Sample with Mean Dependent on Size

Lorenzo Isella |orenzo@|@e||@ @end|ng |rom gm@||@com
Thu Aug 1 12:47:13 CEST 2019


Yes, you are right (and yours is one of the possible cases).
I think this works (I resorted to pen and paper for once)



generate_k <- function(N, n3){

    n1 <- 2+n3
    n2 <- N-n1-n3


    out <- c(rep(1, n1), rep(2, n2), rep(3, n3))

    return(out)
}

where N is the length of the sample, n3 is the number of times I have the number 3 in the sample (n1 and n2 are the same for 1 and 2, respectively).
So far it holds!

L.

On Thu, Aug 01, 2019 at 12:37:47PM +0200, Gerrit Eichner wrote:
>n_1 + ... + n_N = 2(N-1) is requested for integers n_i >= 1.
>
>What about c(rep(2, N-2), 1, 1))?
>
>but I'm afraid that this was not what you really wanted. ;-)
>However, you didn't say if your sample should be random. :-)
>
> Best regards  --  Gerrit
>
>---------------------------------------------------------------------
>Dr. Gerrit Eichner                   Mathematical Institute, Room 212
>gerrit.eichner using math.uni-giessen.de   Justus-Liebig-University Giessen
>Tel: +49-(0)641-99-32104          Arndtstr. 2, 35392 Giessen, Germany
>http://www.uni-giessen.de/eichner
>---------------------------------------------------------------------
>
>Am 01.08.2019 um 12:27 schrieb Lorenzo Isella:
>>Dear All,
>>I cannot unfortunately provide any R code, otherwise I 
>>would not need to post this in the first place.
>>I need to generate a sample of N positive non-zero 
>>integers such that their mean is *exactly* 2(N-1)/N, 
>>i.e. the mean depends on the length of the sample.
>>For a start, we can assume that every integer in my 
>>sample can assume only the values 1, 2 and 3.
>>Any suggestion is appreciated.
>>Cheers
>>
>>Lorenzo
>>
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>>and provide commented, minimal, self-contained, reproducible code.



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