Stating the obvious, but sometimes the obvious is not always obvious. Google's AdWordsAdvisor in WebmasterWorld went on record stating that Google does not use the conversion tracking or Google analytics data to determine the minimum bid for your keywords. That would be evil, if they did, wouldn't it?
And I quote:
Because of persistant rumors and conjecture along these lines, I'd like to clarify that information from Google's conversion tracking and Google Analytics is not used in the calculation of ones minimum bid, nor otherwise incorporated in the calculation of CPC.
I know people who would bet their house that this statement is not accurate. But I would highly doubt Google is looking at a particular advertisers conversion and earnings factors to adjust the minimum bid on that specific keyword phrase.
Forum discussion at WebmasterWorld.