lib/statsample/reliability.rb in statsample-2.0.2 vs lib/statsample/reliability.rb in statsample-2.1.0

@@ -2,24 +2,24 @@
   module Reliability
     class << self
       # Calculate Chonbach's alpha for a given dataset.
       # only uses tuples without missing data
       def cronbach_alpha(ods)
-        ds = ods.dup_only_valid
+        ds = ods.reject_values(*Daru::MISSING_VALUES)
         n_items = ds.ncols
         return nil if n_items <= 1
-        s2_items = ds.to_hash.values.inject(0) { |ac,v| 
+        s2_items = ds.to_h.values.inject(0) { |ac,v| 
           ac + v.variance }
         total    = ds.vector_sum
         
         (n_items.quo(n_items - 1)) * (1 - (s2_items.quo(total.variance)))
       end
       # Calculate Chonbach's alpha for a given dataset
       # using standarized values for every vector.
       # Only uses tuples without missing data
       # Return nil if one or more vectors has 0 variance
       def cronbach_alpha_standarized(ods)
-        ds = ods.dup_only_valid
+        ds = ods.reject_values(*Daru::MISSING_VALUES)
         return nil if ds.any? { |v| v.variance==0}
         
         ds = Daru::DataFrame.new(
           ds.vectors.to_a.inject({}) { |a,i|
             a[i] = ods[i].standardize