I just downloaded the paper. It is unbelievable. Anyway, 18.8 % chance to strike out per plate appearance if you have a last or first name with the letter K. 17.2% is the average. They did not say whether they limited the sample to position players or included pitchers. They show its statistically significant. I feel like driving an ice-pick through my eyeball reading it.
It was "web-published" btw, without peer-review.
[Full disclosoure : both my first name and last name start with 'K'. I can't hit a baseball to save my life.]