Amazon calculates a product’s star ratings based on a machine learned model instead of a raw data average. The model takes into account factors including the age of a rating, whether the ratings are from verified purchasers, and factors that establish reviewer trustworthiness.
I think the product is well written. The book is very informative and its a great resource for anybody planning to take the MCAT or even just to use it as a resource to increase knowledge on this topic. The book covers a lot of the subject and it's really easy to understand. Thanks.