diff --git a/lib/descriptive_statistics/sum.rb b/lib/descriptive_statistics/sum.rb
index d725092..db068fb 100644
--- a/lib/descriptive_statistics/sum.rb
+++ b/lib/descriptive_statistics/sum.rb
@@ -3,6 +3,6 @@ def sum(collection = self)
     values = Support::convert(collection)
     return DescriptiveStatistics.sum_empty_collection_default_value if values.empty?
 
-    return values.inject(:+)
+    return values.reduce(:+)
   end
 end
diff --git a/lib/descriptive_statistics/variance.rb b/lib/descriptive_statistics/variance.rb
index 8c8ad30..ad3f7ab 100644
--- a/lib/descriptive_statistics/variance.rb
+++ b/lib/descriptive_statistics/variance.rb
@@ -4,6 +4,6 @@ def variance(collection = self)
     return DescriptiveStatistics.variance_empty_collection_default_value if values.empty?
 
     mean = values.mean
-    values.map { |sample| (mean - sample) ** 2 }.inject(:+) / values.number
+    values.map { |sample| (mean - sample) ** 2 }.reduce(:+) / values.number
   end
 end