You should use the easy weighting system imdb does.
from http://www.imdb.com/chart/1970s (bottom of page):
"The formula for calculating the Top Rated 50 Titles gives a true Bayesian estimate:
weighted rank (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 50 (currently 500) C = the mean vote across the whole report (currently 6.6)"
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what if nigger meant kite