Class: Vanity::Experiment::Alternative

Inherits:
Object
  • Object
show all
Defined in:
lib/vanity/experiment/ab_test.rb

Overview

One of several alternatives in an A/B test (see AbTest#alternatives).

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(experiment, id, value, participants, converted, conversions) ⇒ Alternative

Returns a new instance of Alternative.



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# File 'lib/vanity/experiment/ab_test.rb', line 9

def initialize(experiment, id, value, participants, converted, conversions)
  @experiment = experiment
  @id = id
  @name = "option #{(@id + 65).chr}"
  @value = value
  @participants, @converted, @conversions = participants, converted, conversions
end

Instance Attribute Details

#conversions ⇒ Object (readonly)

Number of conversions for this alternative (same participant may be counted more than once).



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# File 'lib/vanity/experiment/ab_test.rb', line 36

def conversions
  @conversions
end

#converted ⇒ Object (readonly)

Number of participants who converted on this alternative (a participant is counted only once).



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# File 'lib/vanity/experiment/ab_test.rb', line 33

def converted
  @converted
end

#difference ⇒ Object

Difference from least performing alternative. Populated by AbTest#score.



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# File 'lib/vanity/experiment/ab_test.rb', line 45

def difference
  @difference
end

#experiment ⇒ Object (readonly)

Experiment this alternative belongs to.



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# File 'lib/vanity/experiment/ab_test.rb', line 27

def experiment
  @experiment
end

#id ⇒ Object (readonly)

Alternative id, only unique for this experiment.



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# File 'lib/vanity/experiment/ab_test.rb', line 18

def id
  @id
end

#name ⇒ Object (readonly)

Alternative name (option A, option B, etc).



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# File 'lib/vanity/experiment/ab_test.rb', line 21

def name
  @name
end

#participants ⇒ Object (readonly)

Number of participants who viewed this alternative.



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# File 'lib/vanity/experiment/ab_test.rb', line 30

def participants
  @participants
end

#probability ⇒ Object

Probability derived from z-score. Populated by AbTest#score.



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# File 'lib/vanity/experiment/ab_test.rb', line 42

def probability
  @probability
end

#value ⇒ Object (readonly)

Alternative value.



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# File 'lib/vanity/experiment/ab_test.rb', line 24

def value
  @value
end

#z_score ⇒ Object

Z-score for this alternative, related to 2nd-best performing alternative. Populated by AbTest#score.



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# File 'lib/vanity/experiment/ab_test.rb', line 39

def z_score
  @z_score
end

Instance Method Details

#<=>(other) ⇒ Object 



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# File 'lib/vanity/experiment/ab_test.rb', line 58

def <=>(other)
  measure <=> other.measure 
end

#==(other) ⇒ Object 



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# File 'lib/vanity/experiment/ab_test.rb', line 62

def ==(other)
  other && id == other.id && experiment == other.experiment
end

#conversion_rate ⇒ Object

Conversion rate calculated as converted/participants, rounded to 3 places.



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# File 'lib/vanity/experiment/ab_test.rb', line 48

def conversion_rate
  @conversion_rate ||= (participants > 0 ? (converted.to_f/participants.to_f * 1000).round / 1000.0 : 0.0)
end

#inspect ⇒ Object 



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# File 'lib/vanity/experiment/ab_test.rb', line 70

def inspect
  "#{name}: #{value} #{converted}/#{participants}"
end

#measure ⇒ Object

The measure we use to order (sort) alternatives and decide which one is better (by calculating z-score). Defaults to conversion rate.



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# File 'lib/vanity/experiment/ab_test.rb', line 54

def measure
  conversion_rate
end

#to_s ⇒ Object 



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# File 'lib/vanity/experiment/ab_test.rb', line 66

def to_s
  name
end