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 for reading. specialy kids like me . in my society and school everyone is a big fan of wimpy kid. although some parts were not so good but the part when greg goes with rowly to tbhe beach. so i give this book four stars.