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.
These rolls are by no means "big". I wish the paper-towel industry would start treating us with some respect and lose the misleading and in fact ridiculous "x=y" marketing. Good product. Poor value. Stay away.