Suppose that you conduct a survey and collect data on people's health insurance plan (HMO, PPO, Fee-for-service). You plot the information and find that people who have less restrictive health insurance plans also have higher health care expenditures. From this information you C conclude that higher risk individuals opt into less restrictive insurance plans. conclude that less restrictive health insurance plans leads to higher health expenditures. O cannot tell if this is due to the structure of the plan or if higher risk individuals opt into less restrictive plans