To calculate the overall star rating and percentage breakdown by star, we don’t 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 analyzes reviews to verify trustworthiness.
I liked the explanations, I hated the made up data sets. Regression with real world data is far more challenging than the cosmetic examples in this book. I was looking for a text to support my lecturing, sadly this is not it.