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 analyses reviews to verify trustworthiness.
This is a bad book. The questions are really bad. The related theories and explanations are provided in a hard and mix way. the mind maps which are badly helpful for a short revision before exam. This is a not use students for exam