Answered April 19th, 2019

Ted Williams goes 6-8 in a doubleheader on the final day of the season to finish with a .4057 batting average - the last time a player has finished above .400 in a season.

Who was the last player with a .400 BA in a season with at least 200 AB?
Interpreted as:
Who was the last player with a.400 or higher BA in a season with at least 200 AB?