In the lecture, the average treatment effect was introduced under a binary treatment status, but we often encounter randomized control trials with multiple treatments. Consider the case of three treatment status, where we have no treatment, treatment 1 and treatment 2. Let 011 be a dummy variable taking 1 for treatment 1 and 0 otherwise, and (12 be a dummy variable taking 1 for treatment 2 and 0 otherwise. 1. We consider the following regression y =a+6d1+vd2+e where a, ,8 and 1/ are parameters and e is the error with IE[] = 0. Using ,8 and "f in this regression, explain what you can estimate First, express only the nal outcomes mathematically (no derivations) and second, explain each (no more than 10 words for each). 2. Suppose that we want to estimate the difference of treatment effects between treatment 1 and 2 on average. To this end, consider and expression a specication of a regression when only y, (1 and (52 are available, and denote the key parameter by 6. Express mathematically what 6 measures