Professor E. Z. Stuff has decided that the least squares estimator is too much trouble. Noting that two points determine a line, Dr. Stuff decides to be a little more rigorous and use yj value and yk value in the sample and draws a regression based on the algorithm below, calling the slope of this line the EZ estimator of β1 in the simple regression model. Algebraically, if the y values are ordered, then one y-value and the corresponding x value is (yj, xj) and the second y- value with the corresponding x-value is (yk, xk) the EZ estimation rule is

b(EZ) = (yj - yk)/(xj - xk)

Assuming that all the assumptions of the simple regression model hold:
a. Show that bez is a "linear" estimator
b. Show that bez is an unbiased estimator