"A 2011 Scarborough Research study showed the average age of an NHRA fan was 44.86 — higher only than than the NHL (44.02) and the NBA (44.67)."
It's a pretty crappy stat...
Figure the average life expectancy for an American is about 78, and the average minimum age for someone to attend a sporting event of any kind is 10.
The average of 78 and 10 is 44.
Meaning that at any given event anywhere, it is likely that the average age of people at that event will be 44.
Unless they painstakingly recorded the age of every person entering each event over a long period of time, whether it be the NHRA, NHL, NFL, the range of error is probably larger then the difference between the three cited in the article.
And if you took those numbers they cited to be accurate, they are saying that the average NHL fan is 9 months younger then the average NHRA fan (NHRA = 44 and 10 months, NHL 44 and 1 month roughly). I don't consider 44 years old to be very young.