The idiots at “Think Progress’ have the following ignorant post up:
As Press Secretary Robert Gibbs explained to Garrett, it is Chrysler — not the federal government — that is in charge of selecting which dealerships will be closed. Further, as Nate Silver explained in a post that was published just hours after the Examiner’s initial report yesterday, “There is just one problem with this theory. Nobody has bothered to look up data for the control group: the list of dealerships which aren’t being closed.”
Silver explained, “It turns out that all car dealers are, in fact, overwhelmingly more likely to donate to Republicans than to Democrats — not just those who are having their doors closed.” In all, Silver found that “88 percent of the contributions from car dealers went to Republican candidates and just 12 percent to Democratic candidates,” while, the list of Chrysler dealerships being closed “gave 92 percent of their money to Republicans — not really a significant difference.”
As I write this there are 258 comments over there. Not one of the references the hypergeometric probability distribution, which indicates that not one of their commenters knows what he or she is talking about. Short version: you have a urn full of black and white balls. You take a number of balls out, and don’t put them back in before taking other balls out. If you know the number of balls of each color in the urn, then you can calculate the probability that, by random chance, you will draw out ‘x’ white balls in ‘n’ draws from the urn.
There are 3000 Chrysler dealerships. 750 got told they’re getting closed. Using Nate Silver’s numbers, there are 2640 “Republican” dealerships, and 360 “non-Republican” ones. Of those dealerships, 690 R and 60 non-R dealerships were closed.
Using R, we can calculate the probability that, by random chance, 60 or fewer non-R dealerships would be closed out of 750
phyper (60, 360, 2640, 750)
Unfortunately for Nate, and for the TP big talkers, the result is 3.671535e-05. Or 9 in 250,000.
So yes, that is a significant difference.
Some of the posters over at Nate’s are claiming 3500 dealerships. Keeping all percentages the same, we get
phyper (70, 420, 3080, 875)
That takes the chance down to 8.738693e-06. Less than 9 in 1,000,000. IOW, fail.