mturk question. "Master qualification" means that you have your Master's degree or that you're a master at the type of work?

Sorry if this seems like a stupid question. I just found out about mturk and it's right up my alley so I've registered and am waiting on account approval. When I search for HITs some of them say they require "Master qualification." I looked but saw nothing about this on the site. Does it mean that I've mastered the type of work or that I have obtained my Master's degree?