Better yet, play around with lots of different sorting methods, and look for patterns in the sorting method used (s), the user's data and history (h), and the amount of money the user ends up spending ($).

Maximize $, and don't ask stupid questions like "Would you rather sort by variance, average rating, or Wilson score?"

(I'm pretty sure that's what Amazon is busy doing every day. They're positively brilliant at turning data into money.)