Method: Statsample::StratifiedSample#proportion_standard_error

Defined in:
lib/statsample/multiset.rb

#proportion_standard_error(field, v = 1) ⇒ Object 



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# File 'lib/statsample/multiset.rb', line 288

def proportion_standard_error(field,v=1)
  prop=proportion(field,v)
  sum=@ms.sum_field(field) {|s_name,vector|
    nh=vector.size
    s_size=@strata_sizes[s_name]
    (s_size**2 * (1-(nh / s_size)) * prop * (1-prop) / (nh - 1 ))
  }
  (1.quo(@population_size)) * Math::sqrt(sum)
end