Mine said the West, the lowest common denominator of American speech, although the Midland was a very close second. That would make sense since I live in Colorado.
I think they should have tested with the word "sure": Does it sound like the r-controlled vowel in "bird" (which is the West), or does it sound like the r-controlled vowel in "tour" (which is Midwestern and several other areas)?
Edited: I've been reading the Wipipedia link above, and it certainly points out the limitations of the quiz. Bostonian and North Central were 3rd and 4th place for me and rated fairly highly (about 75%, it looks like), but my accent is nothing like a Bostonian's. They don't pronounce many "r"s, which is why we imitate it by saying: I pahk my cah in Hahvahd yahd (I park my car in Harvard yard), whereas I have pretty growly "r"s.
