stats is fun! haha
yeah i got a 690 for US history too. but yale only wants 2, so that one doesn't really count for me
so your retake was basically pointless. that's why you only retake if you are sure you can do significantly better. but don't worry too much. It's just a subject test.
As for a B in one class, don't sweat it. personally, I don't think stats takes too much math talent. It's just a lot of repetition and practice getting all the different tests and terminology straight.