You can easily change it yourself by assigning stars parameter. For example, if you think that the IMDB rating of 8.0 represents a poor movie with 1 star :-) 8.3 - 2 stars, 8.5 - 3 stars and 8.8 - four stars, then make the parameter stars=8.8,8.5,8.3,8.0
Re: IMDB rating
You can easily change it yourself by assigning stars parameter. For example, if you think that the IMDB rating of 8.0 represents a poor movie with 1 star :-) 8.3 - 2 stars, 8.5 - 3 stars and 8.8 - four stars, then make the parameter stars=8.8,8.5,8.3,8.0