Which Tool Would You Use? (25 points) For each of the following settings explain which procedure you would use to identify a treatment effect. Explain why this tool is appropriate in this setting. In general, you are interested in the labour market returns (wages) to military service. You discover that some countries that previously had compulsory/mandatory military service and then switched to a non-mandatory military, while other countries have always had a non-mandatory military. You are curious whether people who served in the army have different wages from people who served in the navy. You discover that in the past in some countries - with mandatory military service - people who served in the armed forces were randomly sorted into either the army or the navy. In some countries individuals who want to join the military are required to take an aptitude test. People who score below a cutoff are ineligble for military service. In some countries there have been drafts for the military in some years, where people are randomly selected to be in the military. In the USA this has been done using a lottery based on last names