Dear Thomas !
 
 Thank you for you help ! I need and explaination. If I suppress second and third stage what become the variance du to second and third stage ?
 
 I have try this 
     >E3stage<-svydesign(ids=~stage1id, weight=~wei ...) 
 and 
     >E3stage<-svydesign(ids=~stage1id+stage2id+stage3id, weight=~weights...)
 
 And I get the same results
 
 Sincerly.

----- Message d'origine ----
De : Thomas Lumley <tlumley@u.washington.edu>
À : justin bem <justin_bem@yahoo.fr>
Cc : R Maillist <r-help@stat.math.ethz.ch>
Envoyé le : Dimanche, 24 Septembre 2006, 10h04mn 16s
Objet : Re: [R] Complex survey analysis help

On Sun, 24 Sep 2006, justin bem wrote:

> Hi dear all,
>
> I have a complex survey data to analyse. I have a stratified survey with three
> stages level. The first stage is a PPS, but all other are SRSWOR. The solution 
>propose in survey package is to considere PPS as SRS with repetion.

No, the solution proposed is to consider it as PPS with replacement.

> I have try this
>
> E3stage<-svydesign(ids=~stage1id+stage2id+stage3id, fpc=~fpc1+fpc2+fpc3, ...)
>
> This is the value for WOR sampling at all stage. What value should I give to >fpc1 to have the same value of variance that in sampling with repetion ? I try >fpc1<-rep(0,length(data)) I get a error message.

For sampling with replacement you just omit the fpc and specify the first-stage id and the sampling weights

E3stage <-svydesign(ids=~stageid1, weights=~weights)

       -thomas

Thomas Lumley            Assoc. Professor, Biostatistics
tlumley@u.washington.edu    University of Washington, Seattle







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