$4.$ In a survey, people were asked how much meat they ate per week on average. Then their weight, height, and BMI were measured to determine if they were obese by some definition. For each person, it was determined how many pounds they were overweight $($perhaps they used positive numbers for pounds overweight, $0$ for not over weight, and negative numbers for underweight$).$ In this way, they obtained coordinate pairs $($x$,$ y$),$ where x was the number of times they ate meat per week on average, and y was the amount overweight $($or underweight$)$ they were in lbs$.$ It was found that the consumption of meat was strongly correlated with obesity. Does this necessarily mean meat consumption cause obesity? What other factors might be at play here?