added standard deviations

2016-01-11 19:00:53 +01:00
parent e8cb23849a
commit 5b8f710196
4 changed files with 11 additions and 3 deletions
--- a/app/controllers/execution_environments_controller.rb
+++ b/app/controllers/execution_environments_controller.rb
@ -31,7 +31,7 @@ class ExecutionEnvironmentsController < ApplicationController

  def working_time_query
    """
-      SELECT exercise_id, avg(working_time) as average_time
+      SELECT exercise_id, avg(working_time) as average_time, stddev_samp(extract('epoch' from working_time)) * interval '1 second' as stddev_time
      FROM
        (
      SELECT user_id,
@ -62,6 +62,7 @@ class ExecutionEnvironmentsController < ApplicationController
      COUNT(DISTINCT user_id) AS users,
      AVG(score) AS average_score,
      MAX(score) AS maximum_score,
+      stddev_samp(score) as stddev_score,
      CASE
        WHEN MAX(score)=0 THEN 0
        ELSE 100 / MAX(score) * AVG(score)