Measurement error in dependent variable

Imagine the following model: y* = XB +E (2) where X is n x k and B is k x 1 (and k > 2). Assume E[=(X] = 0 and var[=[X] = In. Unfortunately, you do not observe y*. You observe y = y +n (3) and estimate y = X3 +v (4) by OLS. a) (7 points) Write down the least squares problem for equation (4), obtain the first-order conditions, and isolate b (the resulting OLS estimator). b) (7 points) Compute E(b) and describe in details the conditions under which b will be unbiased. Simply stating A3 : E[v|X] = 0 is not an accept- able