Player batting average leaders have the highest percentage of their official at bats end with a base hit. In the past a premium was put on hitters who hit .300 or higher (meaning at least 30% of their official at bats ended with a base hit), the meaningfulness of that number has changed somewhat. Since the beginning of the “Moneyball” era (roughly starting in the early 2000s) a higher emphasis has been placed on on-base percentage and less of an emphasis on batting average. Alternatively, due to the declining offensive numbers throughout baseball having an average of .300 is a more difficult feat than in the past (for example, in 2013 only 24 batters hit above .300; in 2000 54 batters hit above .300).
Batting Average is calculated simply as:
AVG = Hits/At-Bats