(e) (5 points) Show that with random assignment, /, is an unbiased estimator of the average treatment effect on the treated. You must justify every step to receive full credit. (f) (2 points) Suppose there are 400 students in 140A. What is the approximate dis tribution of -A"T. ? What theorem tells us the approximate distribution? (@) (2 points) Under random assignment, is /31 an unbiased estimator of the average treatment effect (ATE)? ATE = k Ef=.E(Y() - Y(0))