diff --git a/lib/sidekiq/statistic/statistic/workers.rb b/lib/sidekiq/statistic/statistic/workers.rb
index 5ea94b6..2fb1dce 100644
--- a/lib/sidekiq/statistic/statistic/workers.rb
+++ b/lib/sidekiq/statistic/statistic/workers.rb
@@ -18,12 +18,12 @@ def display
       end
 
       def display_by_last_status
-        filtered_workers = display.group_by {|worker| worker[:last_job_status] }
+        filtered_workers = display.group_by { |worker| worker[:last_job_status] }
 
         filtered_workers['passed'] ||= []
         filtered_workers['failed'] ||= []
 
-        filtered_workers.transform_keys(&:to_sym)
+        filtered_workers
       end
 
       def display_per_day(worker_name)
diff --git a/test/test_sidekiq/statistic_test.rb b/test/test_sidekiq/statistic_test.rb
index df7d072..732bc20 100644
--- a/test/test_sidekiq/statistic_test.rb
+++ b/test/test_sidekiq/statistic_test.rb
@@ -112,14 +112,14 @@ module Statistic
 
           _(subject).must_be_instance_of Hash
           assert_equal subject.keys.sort,
-                       %i[passed failed].sort
+                       %w[passed failed].sort
 
-          _(subject[:passed]).must_be_instance_of Array
-          _(subject[:failed]).must_be_instance_of Array
-          assert_equal subject[:passed][0].keys.sort,
+          _(subject['passed']).must_be_instance_of Array
+          _(subject['failed']).must_be_instance_of Array
+          assert_equal subject['passed'][0].keys.sort,
                       %i[name last_job_status number_of_calls queue runtime].sort
 
-          assert_equal worker, subject[:passed][0][:name]
+          assert_equal worker, subject['passed'][0][:name]
         end
       end