Sorry for the generalization shimi. I thought for awhile about how to express that idea and couldn't think of a good way. But you're right, education and/or intelligence are not the predictors. I guess it just seems to me that it SHOULD be.

Also, though my statement is essentially indefensible, I did want to point out that I was not saying that all postal workers are uneducated, but rather was referring to the postal workers that had opened fire years ago as being the intersection of the set "uneducated" and the set "postal workers." I apologize.