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.
This describes the panoply of programs available in the R language for the exploration of data. One needs some familiarity with statistics, but it is amazing to see what the crew at AT&T has done with their "language."