闲逛IMDB看到的：

The formula for calculating the Top Rated 250 Titles gives a true Bayesian estimate:

weighted rating (WR) = (v ÷ (v+m)) × R + (m ÷ (v+m)) × C

 where:
  R = average for the movie (mean) = (Rating)
  v = number of votes for the movie = (votes)
  m = minimum votes required to be listed in the Top 250 (currently 1300)
  C = the mean vote across the whole report (currently 6.7)

for the Top 250, only votes from regular voters are considered.

Bottom 100

In order to appear in the Bottom 100 Titles chart the title must have received at least 650 votes.