a$.$ Calculate MSE and MAD for each prediction method. Which prediction method is superior? Explain. b$.$ Calculate MAPE for each prediction method. c$.$ Use the given sales data to make predictions about sales from month $2$ to month $11$ using simple prediction methods. Then calculate each of the following: $(1)$ MSE, $(2)$ MAD, $(3)$ tracking indicators at month $10,$ and $(4)2$s control limits$.$ What can be concluded when comparing the results of simple prediction methods with the previous two techniques?