Batting Average ("Leading the league in hitting."): minimum requirements for averages. Those requirements have changed a lot since early in the previous century.

You can't make up stuff like this. And remember, Plate Appearances (PA) is not the denominator in Batting Average (BA): Hits/AB. Nor in SLG; it's AB there, too. PA is the denominator in On Base Percentage (OBP), which is an average, not a percent. Sit down before you start reading this.

https://www.baseball-reference.com/about/leader_glossary.shtml#min_req

What are the minimum requirements to lead a Rate Stat?

This is a bit of a dicey proposition, because the standards have changed quite a bit throughout time. Here is how we computed them for the website. Thanks to Bill Deane, Gerry Myerson and Total Baseball for clarifying some of these issues.

Batting Average, OBP, Slugging Percentage, OPS

Prior to 1920, a player must have appeared in 60% of the team's games to qualify for a title. This number was rounded to the nearest integer.
From 1920-1937 (unclear, and previously thought to be until 1944), a player must have appeared in 100 games.
From 1920-1948 in the Negro Leagues, a player must have 2.6 at bats per team game.
From 1938-1944, the AL used 400 at bats and the NL stayed with 100 games, as discovered by Paul Rivard of SABR.
From 1945-1956, a player must have 2.6 at bats per team game. Note, however, that from 1951-1954 a player could lead if they still led after the necessary number of hitless at bats were added to their at bat total.
From 1957 to the present, a player must have 3.1 plate appearances per team game. Note, however, that from 1967 to the present a player could lead if they still led after the necessary number of hitless plate appearances were added to their at bat total.

In seasons where a player could still qualify for a title without the minimum plate appearances, we have printed out the altered entry with an asterisk. For instance, in 1995 Mark McGwire didn't have enough PAs to qualify for the league lead in slugging, but when enough hitless at bats were added, so he qualified, his .636 (down from a real value of .685) still managed to place him fifth in the league. The real number is in his batting line and the altered number is in his leaderboard.

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Ted Williams in 1954 did not qualify for Batting Average (BA). Tuesday, April 5, 2016

In 1954 Ted Williams played in 117 games: 526 plate appearances (PA), 386 at bats (AB), American League (AL) leading 136 Bases on Balls (BB) and 133 Hits. Since the 162 game schedule started in the AL in 1961, 502 PA qualifies a batter for rate or average stats. It shouldn't. The criteria in 1954 was silly but Williams should not have qualified for BA. He just didn't have enough AB (#43) or Hits (#24).

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