Amazon Book Rating Mystery

I have an actual Kindle, so Amazon supplies me with “Kindle First”. That means that each month I get to select one new book from (usually) six, for free, to add to my library to read. Amazon tries to include an assortment of genres.

The hope is, I’m sure, that I will review and rate the books, and help generate sales.

At any rate, I often wait for a couple of days at least to start reading the reviews of other Kindle First readers.

Today, I was a bit mystified to see that Amazon apparently includes randomization in their math. This is, according to my high school math teachers, generally Not A Good Thing.

Book One had been rated at 4.7 out of 5 stars, so naturally it shows 4 and 1/2 stars:


Book Two had been rated at 4.8 out of 5 stars, so naturally it shows 5 stars:


Do you see what I see? It appears that both books got numbers of ratings at each level, and yet one book slightly edges out another book.

I’m pretty sure that this isn’t just a weird rounding thing, because the “80%” and “20%” are so dead-on. Amazon normally shows those numbers to the nearest 1’s place.

I don’t have an answer for this. It was just interesting.

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