Read the article, Examining the Association Between School Vending Machine and Children's Body Mass Index by Socioeconomic Status (O'hara & Haynes-Maslow, 2015). It's okay if you don't understand the final analysis. Why do you think the authors decided to track the same group of students, using their data from the 2004 and 2007 surveys, instead of comparing separate groups of fifth and eighth graders from the 2007 survey? QUESTION 32 1 points Save Answer Read the article, Examining the Association Between School Vending Machine and Children's Body Mass Index by Socioeconomic Status (O'hara & Haynes-Maslow, 2015). It's okay if you don't understand the final analysis. Compare the fifth and eighth graders in terms of the number of times they bought salty snacks at school per week, citing the specific measures of center and spread reported in the article