Method: Statsample::StratifiedSample.variance_ksd_wor

Defined in:
lib/statsample/multiset.rb

.variance_ksd_wor(es) ⇒ Object

Source : Cochran (1972)



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# File 'lib/statsample/multiset.rb', line 125

def variance_ksd_wor(es)
n_total=calculate_n_total(es)
es.inject(0){|a,h|
  val=((h['N'].to_f / n_total)**2) * (h['s']**2 / h['n'].to_f) * (1 - (h['n'].to_f / h['N']))
  a+val
}
end