lib/statistics/statistical_test/t_test.rb in ruby-statistics-2.0.2 vs lib/statistics/statistical_test/t_test.rb in ruby-statistics-2.0.3

@@ -34,18 +34,19 @@
                     left_root = sample_left_variance/args[0].size.to_f
                     right_root = sample_right_variance/args[1].size.to_f
 
                     standard_error = Math.sqrt(left_root + right_root)
 
-                    (sample_left_mean - sample_right_mean)/standard_error.to_f
+                    (sample_left_mean - sample_right_mean).abs/standard_error.to_f
                   end
 
         probability = Distribution::TStudent.new(degrees_of_freedom).cumulative_function(t_score)
         p_value = 1 - probability
         p_value *= 2 if tails == :two_tail
 
-        { probability: probability,
+        { t_score: t_score,
+          probability: probability,
           p_value: p_value,
           alpha: alpha,
           null: alpha < p_value,
           alternative: p_value <= alpha,
           confidence_level: 1 - alpha }
@@ -69,10 +70,11 @@
         probability = Distribution::TStudent.new(degrees_of_freedom).cumulative_function(t_score)
 
         p_value = 1 - probability
         p_value *= 2 if tails == :two_tail
 
-        { probability: probability,
+        { t_score: t_score,
+          probability: probability,
           p_value: p_value,
           alpha: alpha,
           null: alpha < p_value,
           alternative: p_value <= alpha,
           confidence_level: 1 - alpha }