A quarter is another way of saying one fourth, in this setting, one fourth of a year = three months. Quarterly means something that happens every 3 months. Edit
Outfielder Ty Cobb, whose career ended in 1928, has the highest batting average in Major League Baseball (MLB) history. He batted .366 over 24 seasons, mostly with the Detroit Tigers. In addition, he won a record 11 batting titles for leading the American League in BA over the course of an entire season.
Batting Average - AVG. What is Batting Average - AVG? A statistic that measures a player's batting ability by comparing the number of hits he has to his number of at bats. A player's batting average is used to evaluate his individual skill at batting. Batting Average does not include walks or hit by pitches. It also does not specify the difference between a single, double, triple, or home run - each are considered to be a single hit.