LSU a 4 Seed in the NCAA Basketball Tournament?

Okay, I know that this is a New Orleans site, but I really need an explanation. LSU won the SEC. LSU finished two games ahead of Tennessee. LSU beat Tennessee by something like 18 points. LSU went deeper into the SEC tournament than Tennessee (or to put in other terms: LSU actually won a game in the SEC tournament).

So, why is LSU a 4 seed and Tennessee is a 2 seed?