Miller et аl. (2021) Miller et аl. (2021) studies the effects оf the Medicаid expansiоns due tо the ACA. (a) What are the questions that the paper asks? (b) What is the main treatment variable? (c) What are the outcomes that the paper examines? (d) Define potential outcomes with respect to mortality. Define the individual treatment effect on mortality. (e) Let index individuals, and let index years. Also, let be an indicator for whether individual has Medicaid in year . Next, let be an indicator for whether is in the treatment group (i.e., the expansion states), and let be an indicator for the post period (i.e., the years after the expansion). Finally, let