Transcript text: Ayomide is reading a recent article with the headline "School lunches make kids overweight." The article cites a study comparing children at two schools. At the school with the lower obesity rate, only a few children eat school lunch. The other school has a greater percentage of obese children, and most of these children eat school lunch. The article doesn't mention that the school with the higher obesity rate is in an area where most people are below the poverty line, nor does it mention that poverty can be a major factor in obesity.
What validity is threatened by the potential confound of poverty?