In a 2018 study by Hurst and Fukuda published in BMJ Open, researchers in Japan surveyed 59,717 participants in Japan who had Type 2 diabetes. Participants were asked to rate their eating speed as Slow, Normal, or Fast. Researchers found that those who rated their eating speeds as Slow or Normal were less likely to be obese than those who rated their eating speed as Fast.

a. Can we conclude that fast eating causes obesity from this study? Why or why not?

b. Can this association be generalized to the entire population of people with Type 2 diabetes? Why or why not?