FiveThirtyEight is a popular blog that uses statistics in creative ways to better understand politics, sports, science and health, economics, and culture. In one article (Hickey, 2015), the author uses z scores to standardize book reviews from www.goodreads.com (which uses a 1 to 5 scale) and movie reviews from www.imdb.com (which uses a scale of 0 to 100) for the top 500 movies that were based on novels.

a. Explain why converting to z scores would be necessary to find out which story had a better book compared to a movie, or which story had a better movie compared to the book.

b. What might be some sampling biases (think back to Chapter 5) found in using these online ratings?