Module: DescriptiveStatistics

Included in:
Stats, Enumerable
Defined in:
lib/descriptive_statistics/sum.rb,
lib/descriptive_statistics/mean.rb,
lib/descriptive_statistics/mode.rb,
lib/descriptive_statistics/range.rb,
lib/descriptive_statistics/stats.rb,
lib/descriptive_statistics/median.rb,
lib/descriptive_statistics/number.rb,
lib/descriptive_statistics/variance.rb,
lib/descriptive_statistics/percentile.rb,
lib/descriptive_statistics/class_methods.rb,
lib/descriptive_statistics/percentile_rank.rb,
lib/descriptive_statistics/support/convert.rb,
lib/descriptive_statistics/standard_deviation.rb,
lib/descriptive_statistics/descriptive_statistics.rb

Defined Under Namespace

Modules: Support Classes: Stats

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.empty_collection_default_value ⇒ Object 



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# File 'lib/descriptive_statistics/class_methods.rb', line 5

def empty_collection_default_value
  @empty_collection_default_value
end

.empty_collection_default_value=(value) ⇒ Object 



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# File 'lib/descriptive_statistics/class_methods.rb', line 9

def empty_collection_default_value=(value)
  @empty_collection_default_value = value
  DescriptiveStatistics.instance_methods.each { |m| default_values[m] = value }
end

Instance Method Details

#descriptive_statistics(&block) ⇒ Object 



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# File 'lib/descriptive_statistics/descriptive_statistics.rb', line 2

def descriptive_statistics(&block)
  return { :number => self.number(&block),
           :sum => self.sum(&block),
           :variance => self.variance(&block),
           :standard_deviation => self.standard_deviation(&block),
           :min => self.min(&block),
           :max => self.max(&block),
           :mean => self.mean(&block),
           :mode => self.mode(&block),
           :median => self.median(&block),
           :range => self.range(&block),
           :q1 => self.percentile(25, &block),
           :q2 => self.percentile(50, &block),
           :q3 => self.percentile(75, &block) }
end

#mean(collection = self, &block) ⇒ Object 



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# File 'lib/descriptive_statistics/mean.rb', line 2

def mean(collection = self, &block)
  values = Support::convert(collection, &block)
  return DescriptiveStatistics.mean_empty_collection_default_value if values.empty?

  values.sum / values.number
end

#median(collection = self, &block) ⇒ Object 



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# File 'lib/descriptive_statistics/median.rb', line 2

def median(collection = self, &block)
  values = Support::convert(collection, &block)
  return DescriptiveStatistics.median_empty_collection_default_value if values.empty?

  values.percentile(50)
end

#mode(collection = self, &block) ⇒ Object 



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# File 'lib/descriptive_statistics/mode.rb', line 2

def mode(collection = self, &block)
  values = Support::extract(collection, &block)
  return if values.to_a.empty?

  values
    .group_by { |e| e }
    .values
    .max_by(&:size)
    .first
end

#number(collection = self, &block) ⇒ Object 



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# File 'lib/descriptive_statistics/number.rb', line 2

def number(collection = self, &block)
  values = Support::extract(collection, &block)

  values.to_a.size.to_f
end

#percentile(p, collection = self, &block) ⇒ Object 



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# File 'lib/descriptive_statistics/percentile.rb', line 2

def percentile(p, collection = self, &block)
  values = Support::convert(collection, &block)

  return DescriptiveStatistics.percentile_empty_collection_default_value if values.empty?
  return values.first if values.size == 1

  values.sort!
  return values.last if p == 100
  rank = p / 100.0 * (values.size - 1)
  lower, upper = values[rank.floor,2]
  lower + (upper - lower) * (rank - rank.floor)
end

#percentile_rank(p, collection = self, &block) ⇒ Object

percent of cases that are at or below a score



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# File 'lib/descriptive_statistics/percentile_rank.rb', line 3

def percentile_rank(p, collection = self, &block)
  values = Support::convert(collection, &block)
  return DescriptiveStatistics.percentile_rank_empty_collection_default_value if values.empty?

  return (((values.sort.rindex { |x| x <= p } || -1.0) + 1.0)) / values.number * 100.0
end

#range(collection = self, &block) ⇒ Object 



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# File 'lib/descriptive_statistics/range.rb', line 2

def range(collection = self, &block)
  values = Support::convert(collection, &block)
  return DescriptiveStatistics.range_empty_collection_default_value if values.empty?

  values.max - values.min
end

#standard_deviation(collection = self, &block) ⇒ Object 



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# File 'lib/descriptive_statistics/standard_deviation.rb', line 2

def standard_deviation(collection = self, &block)
  values = Support::convert(collection, &block)
  return DescriptiveStatistics.standard_deviation_empty_collection_default_value if values.empty?

  Math.sqrt(values.variance)
end

#sum(collection = self, &block) ⇒ Object 



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# File 'lib/descriptive_statistics/sum.rb', line 2

def sum(collection = self, &block)
  values = Support::convert(collection, &block)
  return DescriptiveStatistics.sum_empty_collection_default_value if values.empty?

  return values.reduce(:+)
end

#variance(collection = self, &block) ⇒ Object 



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# File 'lib/descriptive_statistics/variance.rb', line 2

def variance(collection = self, &block)
  values = Support::convert(collection, &block)
  return DescriptiveStatistics.variance_empty_collection_default_value if values.empty?

  mean = values.mean
  values.map { |sample| (mean - sample) ** 2 }.reduce(:+) / values.number
end