st: probability weight defining

["Jin king" <kingmax_0@hotmail.com>]

Hi,
I have a survey sample to be weighted using probability weight. 
It is not kind of a simple random sampling problem. The observations are 
drawn from (region, size) combinations, say 4 regions(North, east, west and 
south) and 3 sizes( small medium and large) . Total combinations are 12. 
The numbers of observations in each combination are S1, S2,...S12 
respectively.

And I know the populations for each combination, say, N1, N2,..., N12. I 
need to weight the data for consideration of both region and size. 
How to define the p-weight using SVYSET command? Can I use pw_j = Sj/Nj, 
where  j =1,2,...,12? (say,  replace pw  = S4/N4 if region == a & size 
==b...)

Thanks,

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