[R] How to do bootstrap for the complex sample design?

[Robert A LaBudde]

At 01:38 AM 11/4/2010, Fei xu wrote:

>Hello;
>
>Our survey is structured as : To be investigated area is divided 
>into 6 regions,
>within each region, one urban community and one rural community are 
>randomly selected,
>then samples are randomly drawn from each selected uran and rural community.
>
>The problems is that in urban/rural stratum, we only have one sample.
>In this case, how to do bootstrap?
>
>Any comments or hints are greatly appreciated!
>
>Faye

Just make a table of your data, with each row corresponding to a 
measurement. You columns will be Region, UrbanCommunity, 
RuralCommunity and your response variables.

Bootstrap resampling is just generating random row indices into this 
table, with replacement. I.e.,

index<- sample(1:N, N, replace=TRUE)

Then your resample is myTable[index,].

Because you chose UrbanCommunity and RuralCommunity randomly, this 
shouldn't be a problem. The fact that you choose a subsample size of 
1 means you won't be able to estimate within-region variances unless 
you make some serious assumptions (e.g., UrbanCommunity effect 
independent of Region effect).

================================================================
Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: ral at lcfltd.com
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