Statistics and Probability Dictionary
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Optimum allocation refers to a method of sample allocation, used with stratified
sampling. Optimum allocation is designed to provide the most precision for the
least cost. Based on optimal allocation, the best sample size for stratum h
nh = n * [ ( Nh * Sh ) / sqrt( ch
) ] / [ Σ ( Ni * Si )
/ sqrt( ci ) ]
where nh is the sample size for stratum h, n is total sample
size, Nh is the population size for stratum h, Sh is
the standard deviation of stratum h, and ch is the direct
cost to sample an individual element from stratum h. Note that ch
does not include indirect costs, such as overhead costs.