No more things should be presumed to exist than are absolutely necessary, i.e., the fewer assumptions an explanation of a phenomenon depends on, the better the explanation.
- William of Ockham (c. 1287–1347)
This is sheer haberdashery.
One can deduce that Rihanna’s presence, or lack thereof, has no bearing on the quality at which any given NBA game is played: there simply isn’t a preponderance of evidence from which to draw any conclusive theses.
Selection bias is also at play – given the rate at which musicians attend basketball games, there is bound to be statistical irregularity due to the frequency and random generation of “relevant” analysis – particularly given the arbitrary selection of particular players and criterion through which to evaluate said players.
In conclusion: Rihanna is almost certainly inconsequential in regards to the relationship between her relative proximity to NBA players and their consequent performance. Perhaps further empirical research might reveal further data to the contrary, but the Principle of Occam’s Razor suggests that this is a highly improbable conclusion to bear itself out.