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.
A very good book. I enjoyed it even as an adult as it took me back to a lot of childhood memories. I can totally relate to this book. A good read for any age. Very funny. For an adult reader, this book will seem short as half of it is pictures. But still worth it. Very funny.