Likelihood of Unanimous Precincts

[Tom_Tildrum]

@smithsb

There were a few Ohio precincts that were 100% Obama.

Also 37 in Chicago and 59 in Philly.

[Chronos]

Think of it like choosing socks from a drawer with the lights out. There are 960 black socks and 40 dark blue socks. They are hard to tell apart without the lights on but you don’t want to wake your spouse so you pull socks at random. You pull out 500 socks. What are the chances you pull all black socks?

Except that assuming the existence of those dark blue socks is precisely what you shouldn’t be doing, since the question is whether any dark blue socks exist.

Think of it this way: We’re not asking the question of a particular precinct, which we know to have a particular percentage. We’re asking the question of a general set of precincts which are all demographically similar to that known precinct. Thus, we know that any given voter in such a demographically-similar precinct has a 96% chance of voting for Obama, but we don’t know that 96% of the voters in that precinct support Obama.