Data Proves Amazon Reviews with “Free or Discounted Disclaimer” Biased [video]

At 1:25 of the video they show a chart indicating the review star spread across all reviews. I was surprised to see how high the average review is for items.

My thought is the average would be lower due to the fact more people tend to review an item when they are dissatisfied. Perhaps people are trying to confirm their purchase decision by rating things higher?

I was unaware the company existed. I've been using fakespot (http://fakespot.com/) for a few months now and it's become a vital part of deciding which products to buy.