Hugo Kornelis (8/6/2012)
sknox (8/6/2012)
Hugo, I can see why you didn't want the "choose 3" text there -- for many of us it takes a question with 31 possible answers (2^5 -1 since I believe choosing 0 answers is not an option in this system down to a choice of 3 (if you got the non-unique clustered index) or 6 (if you weren't sure of the non-unique clustered index.)I prefer not to think of it as a single question with 31 possible answers, but as six simple yes/no questions (with the additional information that at least two of them need to have a "yes" answer).
((And for the pedantic among us, it's actually 57 possible answers (2^6 - 1 - 6) as I did provide the note about "multiple answers" being correct - so all six options with only one tick can be discarded, as can the option with no correct answer. And for the record, the QotD software forces the author to mark at least one answer as correct, and will automatically present the answer options as either radio buttons or tick marks depending on the number of correct options.))
Actually by "for many of us" I was indicating the fact that the unique non-clustered option was pretty much a given (at this time 90% of respondents get this one correct.) That leaves 5 answers, of which at least one must be selected to make it a true multiple answer question -- that gives us the 2^5-1 = 31.
But then I did mess up in the "choose 3" calculation. If you were correctly confident of the non-unique clustered index answer, then you'd have 2 and need one more out of 4. If you weren't confident of that one, you'd need 2 out of 5, of which there are 10 unique combinations.