[R] How to use Subpopulation data?

David Winsemius dwinsemius at comcast.net
Fri Oct 2 16:38:29 CEST 2009

On Oct 1, 2009, at 6:06 AM, KABELI MEFANE wrote:

> Dear Helpers
> I have a sample frame and i have sampled from it using three methods  
> and now i want to calculate the statistics but i only get the  
> population parameters.
> H <- matrix(rnorm(100, mean=50000, sd=5000))
> sampleframe=data.frame(type=c(rep("H",100)),value=c(H))
> sampleframe
> str=strata(sampleframe,c("type"),size=c(20,), method="srswor")
> sample.strat<-getdata(sampleframe,str)
> sample.strat

If you want the number of rows in sample.strat then length(H) is the  
wrong approach since that is the original (unsampled) object.

> length(H)
> i get:
> length(H)
> [1] 100
> Desire to get:
> length(H)
> [1] 20

I cannot tell what packages you have loaded and strata is not in the  
sampling package which I guessed (wrongly) was where you were getting  
"getdata". When you post code you should precede that code with calls  
that load any non-base packages.

In later posting you ask for ways to calculate "the sum" but you do  
not say what it is that you want the sum of.... . Our abilities to  
read minds is extremely limited.

David Winsemius

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