I'm no population expert so here are some facts that made me say "really?" (casual rounding errors are mine):

• 50% of the population over 15 is never married. Wow, and is it legal to get married at 15 in Mass? In Alabama even?
• 50% of the population is non-white. Even if you include all the stops on the Orange line this seems high to me.
• 45% of the population is enrolled in college. Even in a college town that seems outrageously high. But it may explain the marriage stats. On the other hand that would be almost everyone aged 18-45 (50%).
• Some of the margins for error are ridiculously high. "Responsible for grandchildren" is 30% (of the 400k aged 30+) plus or minus 10%. And no, I'm not sure what that means.
• 70% of the population was born in the US. This one actually strikes me as about right. It also makes sense of the statistic that only 65% of homes are "English Only." I have friends who speak to their parents only in Greek, Urdu, Estonian, or Italian but you'd never know it unless you stop by their parent's house for dinner.
• Only 0.3% of the population is involved in agriculture or fishing. I guess the fishermen and cranberry bogs aren't in Suffolk county.
• 60% of the population lives in a structure that was built before 1940.