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 purchased this book thinking it would be something more than what it was. Skimming through, this book is probably best for a high school freshman at best. I hate to give such a review to an independent publisher because I too am a writer, but please put in the description it is more of a youth book than a "masterclass."