I have an music items that are scored by users between 1 to 5, and I need a formula to get the 5 most scored items.
But obviously an item that get 3.5 average score
You can use Bayesian estimates to calculate weighted voting.
IMDb (Internet Movie Database) uses this calculation to determine its IMDb Top 250. (Note: IMDb uses 10 stars but the formulas are identical using 5 stars).
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 3000)
- C = the mean vote across the whole report (currently 6.9)
IMDb Reference
Wikipedia Reference