1. We want to regress crime rates (Y variable) by U.S. state on incarceration rates (X variable) by U.S. state, to find out whether putting people in jail reduces crime. For each option presented below, explain why it would or wouldn't make a good instrument. ~ a) GDP per capita by US state b) The number of lawsuits aimed at reducing prison overcrowding c) The political party of the governor in each state 2. a) Can instrument relevance be tested? If so, how?~ b) Can instrument exogencity be tested? If so, how?~