Well, IIRC, there is no gambling stat like in 1&2. Plus I do believe Chris Avellone said the higher the luck, the better your odds. If I find the E3 video, I'll post it for you

Edit- http://www.youtube.com/watch?v=8wF4Yo-FxNY is the video, but correction, it's Jason Bergman who mentions the luck stat bit, not Chris Avellone. At about 4:05ish, he mentions that basically the higher your luck skill, the higher your chances of success are. I hope this answers your question.