Part 111 Anderson, Dobkin, and Gross (2014) study the effect of health insurance coverage on emergency department visits by a regression discontinuity (RD) design. They leverage the fact that many private health insurance plans covered dependents who are full-time students until age 23. As shown in the following figure, there is a sharp increase in the uninsured rate across age 23: A. Share Uninsured Figure source: Anderson, Dobkin, and Gross (2014) 1. [9 points] In this RD design, what should be the outcome variable, treatment variable, and running variable? Part 111 Anderson, Dobkin, and Gross (2014) study the effect of health insurance coverage on emergency department visits by a regression discontinuity (RD) design. They leverage the fact that many private health insurance plans covered dependents who are full-time students until age 23. As shown in the following figure, there is a sharp increase in the uninsured rate across age 23: A. Share Uninsured Figure source: Anderson, Dobkin, and Gross (2014) 1. [9 points] In this RD design, what should be the outcome variable, treatment variable, and running variable