I’d never claim that I’m smart, but I have two engineering degrees, and I got picked to serve both times I got called(eminent domain and rock cocaine). Not sure about demographics being the deciding factor, either. Once I was married, once I was not. Once I was one political party, once I was non-delcared. I honestly think that it has more to do with if you can miss a good amount of time. With my company, a two-week stint is no problem…. they’ll allow it, and the court knows it.
I will say this, the one person who got sent home (after the judge and lawyers screend her prior to making their final selections), claimed that she already thought the person was guilty, and would not change her mind. The judge and lawyers explained and grilled her about the “innocent until proven guilty” concept. She said she didn’t care, that her mind was made up. And off to home she went, fully serving her duty.
I was also a foreman once. And in my anal-organized way, I charted out all the things we needed to base our decision on, and the verdict became very obvious. We deliberated for all of a half or three-quarters of a day, and there were intially a lot of people on the fence.