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).
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