Interarrival times to a coffee shop is random with unknown distribution. A shop owner wants to approximate daily interarrival times using the first 20 arrivals of the day, denoted as X, X2, X3, X20, with one of the following estimators: 30X3+40X13+50X 110 A = 0.4X +0.85X14-0.15X10 2X + 2X10 + X20 5 A3 = A = 2aX + (1-2a)X10 where 0as 3X10 + 4X20 8 As a) Determine the bias and precision for each estimator. Write down the MSE expressions. b) Which estimator is better A, or A4. (Use MSE).