Method: Statsample::Factor.kmo_univariate

Defined in:
lib/statsample/factor.rb

.kmo_univariate(matrix, var) ⇒ Object

Kaiser-Meyer-Olkin measure of sampling adequacy for one variable.



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# File 'lib/statsample/factor.rb', line 78

def self.kmo_univariate(matrix, var)
  if var.is_a? String
    if matrix.respond_to? :fields
      j=matrix.fields.index(var)
      raise "Matrix doesn't have field #{var}" if j.nil?
    else
      raise "Matrix doesn't respond to fields"
    end
  else
    j=var
  end
  
  q=anti_image_correlation_matrix(matrix)
  n=matrix.row_size
  
  sum_r,sum_q=0,0
  
  n.times do |k|
    if j!=k
      sum_r+=matrix[j,k]**2
      sum_q+=q[j,k]**2
    end
  end
  sum_r.quo(sum_r+sum_q)
end