Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
Not the usual good quality from Miss Bella. Lots of loose ends which are to be tied up - in the next book. Honestly - I won’t be paying for another book when a few more chapters would have wrapped this one up.