Extract method to calculate stddev percentage

Author: rafaelfranca

lib/results_table_builder.rb

@@ -87,14 +87,14 @@ def build_row(bench_name)
 
   def build_base_columns(row, base_t, base_rss)
     row << mean(base_t)
-    row << 100 * stddev(base_t) / mean(base_t)
+    row << stddev_percent(base_t)
     row << base_rss if @include_rss
   end
 
   def build_comparison_columns(row, other_ts, other_rsss)
     other_ts.zip(other_rsss).each do |other_t, other_rss|
       row << mean(other_t)
-      row << 100 * stddev(other_t) / mean(other_t)
+      row << stddev_percent(other_t)
       row << other_rss if @include_rss
     end
   end
@@ -136,4 +136,8 @@ def mean(values)
   def stddev(values)
     Stats.new(values).stddev
   end
+
+  def stddev_percent(values)
+    100 * stddev(values) / mean(values)
+  end
 end