For each movie that received more than 3 reviews, what is the average rating?
return movies ;return reviews of  #1 ;return number of #2 for each #1 ;return #1 where  #3 is  higher than 3 ;return ratings of  #4 ;return average #5 for each #4
['select', 'project', 'group', 'comparative', 'project', 'group']