I implemented this in a rating system once. Got multiple bug reports, people complained that the system calculates averages wrong, because there are two ratings and the average is obviously not the number they are seeing.
Just sort the objects in the order determined by this formula and only show the ratings given by users in the interface.
The people reporting the problems were the users, and yes, this was bias, as they expected averages. That was exactly my point — while the statistics behind this method are sound, it is not what people expect. Building systems that don't do what people expect is difficult.