I feel, you chose the wrong example to start with
with The Godfather at 9.2 and The Martian at 8.1, the precise point IMDB wants to make to the user who has not yet seen both the movies is given the choice, watch The Godfather first.
we can debate on how that number came, i.e.
- if 92 liked and 8 didn’t like or
- 100 people rated on scale of 1 to 10 and the average of all was 9.2