Seriously, how many studies are there that show this?
Nothing about the nature of the foul, the positioning of the players on the court, what they were doing, etc. Those are all factors on how and why fouls are called.
Trying to measure something that subjective by statistical analysis must have been a daunting task. The study reads like junk science - but it sounds like the researchers have a great future in developing stats that can accumulate grants. Follow the money.