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.
Bought it, loved it at first. But broke down after only a year. Customer service was very poor and slow to respond. They even wrote to say that may drop my refund case because their customer service Dept is over loaded.