Class: Statsample::Test::ChiSquare::WithMatrix

Inherits:
Object
  • Object
show all
Defined in:
lib/statsample/test/chisquare.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(observed, expected = nil) ⇒ WithMatrix

Returns a new instance of WithMatrix.



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# File 'lib/statsample/test/chisquare.rb', line 7

def initialize(observed, expected=nil)
  @observed=observed
  @expected=expected or calculate_expected
  raise "Observed size!=expected size" if @observed.row_size!=@expected.row_size or @observed.column_size!=@expected.column_size
  @df=(@observed.row_size-1)*(@observed.column_size-1)
  @value=compute_chi
end

Instance Attribute Details

#df ⇒ Object (readonly)

Returns the value of attribute df.



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# File 'lib/statsample/test/chisquare.rb', line 5

def df
  @df
end

#value ⇒ Object (readonly)

Returns the value of attribute value.



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# File 'lib/statsample/test/chisquare.rb', line 6

def value
  @value
end

Instance Method Details

#calculate_expected ⇒ Object 



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# File 'lib/statsample/test/chisquare.rb', line 14

def calculate_expected
  sum=@observed.total_sum
  @expected=Matrix.rows( @observed.row_size.times.map {|i|
    @observed.column_size.times.map {|j|
      (@observed.row_sum[i].quo(sum) * @observed.column_sum[j].quo(sum))*sum
    }
  })          
end

#chi_square ⇒ Object 



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# File 'lib/statsample/test/chisquare.rb', line 25

def chi_square
  @value
end

#compute_chi ⇒ Object 



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# File 'lib/statsample/test/chisquare.rb', line 31

def compute_chi
    sum=0
    (0...@observed.row_size).each {|i|
      (0...@observed.column_size).each {|j|
      sum+=((@observed[i, j] - @expected[i,j])**2).quo(@expected[i,j])
      }
    }
    sum
end

#probability ⇒ Object 



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# File 'lib/statsample/test/chisquare.rb', line 28

def probability
  1-Distribution::ChiSquare.cdf(@value.to_f,@df)
end

#to_f ⇒ Object 



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# File 'lib/statsample/test/chisquare.rb', line 22

def to_f
  @value
end