What is the average rating of songs produced by female artists?
SELECT avg(T2.rating) FROM artist AS T1 JOIN song AS T2 ON T1.artist_name  =  T2.artist_name WHERE T1.gender  =  "Female"
average rating of songs = AVG(song.rating); produced by female artists refers to filtering artists by gender = 'Female'; joining artist and song tables on artist_name to match artists with their songs;