2. Make Mine a Large In the 2009 New York Times piece "Excess Pounds, but Not Too Many, May Lead to Longer Life," author Roni Caryn Rabin reported: Being overweight won't kill you-it may even help you live longer. That's the latest from a study that analyzed data on 11,326 Canadian adults, ages 25 and older, who were followed over a 12-year period. The report ... found that overall, people who were overweight but not obese-defined as a body mass index of 25 to 29.9- were actually less likely to die than people of normal weight, defined as a B.M.I. of 18.5 to 24.9. By contrast, people who were underweight, with a B.M.I. under 18.5, were more likely to die than those of average weight. Their risk of dying was 73% higher than that of normal weight people. a. Although this article doesn't describe an experiment, it does imply that being a little overweight may lead to a longer life. Identify at least one confounding variable that may compromise the validity of this inference and support your choice