Here is the only prediction you can be confident in for Saturday's Champions League final: Paris Saint-Germain will have more possession than Inter Milan.
Across their 16 matches this season, PSG averaged 60.1% possession -- more than all but Manchester City and Bayern Munich. Inter Milan, meanwhile, controlled just 47% of the ball -- less possession than 22 of the 36 teams that qualified for the league phase.
But possession doesn't equal wins. See: Manchester City. And possession doesn't even necessarily equal better chances or more attempts on goal.