Complex sampling survey _ Use of survey package

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From: "Ahoussou Sylvie" <sylvie.ahoussou at antilles.inra.fr>
Sent: Friday, September 12, 2008 9:48 AM
To: "Thomas Lumley" <tlumley at u.washington.edu>
Subject: Re: [R] Complex sampling survey _ Use of survey package

Thanks for your answer

I think I made a mistake when I recopied the 5 first rows of my database

here is the table with the comlums of interest

num esp fpc1 Totanim Id_An
2045 G 551 12 10
2046 C 551 68 11
2070 G 551 9 50
2070 S 551 9 51
2070 S 551 9 52

yes Totanim is the total number of animals in the farm and num is the total 
number of herds

Do you mean 'fpc1 is the total number of herds'? That is what your 
svydesign() call says.

I keep on obtaining this error message

clustot<-svydesign(id=~num+ ~ Id_An, fpc=~fpc1+~Totanim, data=tab1)

Erreur dans as.fpc(fpc, strata, ids) :
 FPC implies >100% sampling in some strata.

Well, we seem to have either a bug or a problem with the data.

If you do
   options(error=recover)
before the svydesign() call you can go into as.fpc() and look at the data.

As an example;

Error in as.fpc(fpc, strata, ids) :
   FPC implies >100% sampling in some strata.

Enter a frame number, or 0 to exit

1: svydesign(id = ~dnum + snum, fpc = ~fpc1 + I(pmin(fpc2, 4)), data = 
apiclus2)
2: svydesign.default(id = ~dnum + snum, fpc = ~fpc1 + I(pmin(fpc2, 4)), 
data = apiclus2)
3: as.fpc(fpc, strata, ids)
Selection: 3
Called from: eval(expr, envir, enclos)
Browse[1]> which(sampsize>popsize, arr.ind=TRUE)
     row col
22   22   2
23   23   2
24   24   2
...

Browse[1]> sampsize[22,2]
[1] 5
Browse[1]> popsize[22,2]
[1] 4
Browse[1]> ids[22,]
    dnum    snum
22  200 200.841

So in this case one of the problems is in dnum 200, snum 841, where the 
population size was specified as 4 but the sample size is 5.

 	-thomas

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