The three pictures below is a dabaset of monthy sparking sales from January 1980 to December 1994. The numbers are in thousands of units sold. Answer the following questions:

1. What is the MAPE ( Mean absolute percentage Error) of the seasonal naive forecast in the validation period? Consider 12 values in the validation period. (show your work)

the answer is between: a)20.01; b)20.74; c)18.75

2) What is the RMSE ( Root Mean Squared errors) of the non-seasonal Naive forecast in the validation period? Consider 12 values in the validation period. SHOW YOUR WORK!

the answer is between: a)4205.36; b)4032.56; c)4155.51