To calculate the overall star rating and percentage breakdown by star, we do not use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
I got a 4-pack. Yes, I recognize they are cheap. But, seriously? One didn't work at all, and one has gouges or some kind of flaw in the roller, so that every single copy has blobs on it. I'm on #3, and haven't opened #4 yet, I cringe at what surprises are in store when I open that one.