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 got this Spanish textbook at a very reasonable price on Amazon, in new condition. I got the book itself because my spanish class required it. Not so crazy abouth the book because it doesn't give answers to the exercises.