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.
I have always enjoyed the music of Lang Lang. This album was not a disappointment. In addition the music sheets are easy to read, and are written so that you could come close to playing the piece like Lang Lang.