What conference has most NCAA final four appearances in past 15 years?

Answer 1

The "past 15 years" would not include the current year (2013). For the 15 years

of 1998-2012, the Atlantic Coast Conference (ACC) had 12 Final Four teams, as did the Big Ten-- except that NCAA infractions forced Ohio State to vacate its 1999 appearance, which would make the Big Ten's count 11. The Big East had ten teams during this timeframe.

Over the "last 15 years," which is what you might mean, the Big Ten has had 13 teams (including the vacated Ohio State appearance); the Big East 12; and the ACC 11. The "last 15 years" would be 1999-2013, but your use of "past" is the more correct term of art. By definition, the "last 15 years" would suggest that the event had come to an end and that here would be no more,

which is not expected to be the case.