Contents

module Laboratory
  module Calculations
    module ConfidenceLevel
      def self.calculate(n1:, p1:, n2:, p2:) # rubocop:disable Naming/MethodParameterName
        cvr1 = p1.fdiv(n1)
        cvr2 = p2.fdiv(n2)

        z = ZScore.calculate(
          n1: n1,
          p1: cvr1,
          n2: n2,
          p2: cvr2
        )

        percentage_from_z_score(-z).round(4)
      end

      def self.percentage_from_z_score(z) # rubocop:disable Naming/MethodParameterName, Metrics/AbcSize, Metrics/MethodLength
        return 0 if z < -6.5
        return 1 if z > 6.5

        factk = 1
        sum = 0
        term = 1
        k = 0
        const = 0.3989422804

        loop_stop = Math.exp(-23)
        while term.abs > loop_stop do # rubocop:disable Style/WhileUntilDo
          term =
            const * ((-1)**k) * (z**k) / (2 * k + 1) / (2**k) * (z**(k + 1)) / factk # rubocop:disable Layout/LineLength

          sum += term
          k += 1
          factk *= k
        end

        sum += 0.5
        1 - sum
      end
    end
  end
end

Version data entries

6 entries across 6 versions & 1 rubygems

Version	Path
laboratory-0.1.7	lib/laboratory/calculations/confidence_level.rb
laboratory-0.1.6	lib/laboratory/calculations/confidence_level.rb
laboratory-0.1.5	lib/laboratory/calculations/confidence_level.rb
laboratory-0.1.4	lib/laboratory/calculations/confidence_level.rb
laboratory-0.1.3	lib/laboratory/calculations/confidence_level.rb
laboratory-0.1.2	lib/laboratory/calculations/confidence_level.rb