Table: psi_factor_episodes_2
Columns: series
title
directed_by
written_by
original_air_date

Question: What series number was directed by milan cheylov and written by will dixon?
SQL: SELECT AVG("series") FROM psi_factor_episodes_2 WHERE "directed_by" = 'milan cheylov' AND "written_by" = 'will dixon'

Question: What series # had an original air date of november 30, 1996?
SQL: SELECT MIN("series") FROM psi_factor_episodes_2 WHERE "original_air_date" = 'november 30, 1996'