This study analyzed data on all major league baseball players from one season ( 715 observations ) , the 1989 regular season , .
Winfree and Molitor ( 2007 ) chose to analyze multiple seasons .
This study analyzed data on all major league baseball players from one season ( 715 observations ) , the 1989 regular season , whereas Winfree and Molitor ( 2007 ) chose to analyze multiple seasons .