Some stats are relative to league average (+ ⇒ above average, − ⇒ below average).
Personal fouls include all fouls, not just fouls called by this referee.
Home vs. Visitor
For example, if the home team outscored the visiting team by 3.5 points per game in games officiated by this referee and the league average was 3.0 points per game,
then the associated "Relative to Average" column would have a value of 3.5 - 3.0 = +0.5.