a) Develop a simple three-period moving average model for forecasting the IBM stock.

b) Compute MAD, MSE, and MAPE.

Closing Stock Prices DJ Industrials Date \begin{tabular}{|r|l|l|l|l|l} & IBM & INTC & CSCO & GE & \multicolumn{1}{l}{ Index } \\ \hline 9/3/2010 & $127.58 & $18.43 & $21.04 & $15.39 & 10447.93 \\ \hline 9/7/2010 & $125.95 & $18.12 & $20.58 & $15.44 & 10340.69 \\ \hline 9/8/2010 & $126.08 & $17.90 & $20.64 & $15.70 & 10387.01 \\ \hline 9/9/2010 & $126.36 & $18.00 & $20.61 & $15.91 & 10415.24 \\ \hline 9/10/2010 & $127.99 & $17.97 & $20.62 & $15.98 & 10462.77 \\ \hline 9/13/2010 & $129.61 & $18.56 & $21.26 & $16.25 & 10544.13 \\ 9/14/2010 & $128.85 & $18.74 & $21.45 & $16.16 & 10526.49 \\ \hline 9/15/2010 & $129.43 & $18.72 & $21.59 & $16.34 & 10572.73 \\ 9/16/2010 & $129.67 & $18.97 & $21.93 & $16.23 & 10594.83 \\ \hline 9/17/2010 & $130.19 & $18.81 & $21.86 & $16.29 & 10607.85 \\ 9/20/2010 & $131.79 & $18.93 & $21.75 & $16.55 & 10753.62 \\ \hline 9/21/2010 & $131.98 & $19.14 & $21.64 & $16.52 & 10761.03 \\ 9/22/2010 & $132.57 & $19.01 & $21.67 & $16.50 & 10739.31 \\ 9/23/2010 & $131.67 & $18.98 & $21.53 & $16.14 & 10662.42 \\ 9/24/2010 & $134.11 & $19.42 & $22.09 & $16.66 & 10860.26 \\ 9/27/2010 & $134.65 & $19.24 & $22.11 & $16.43 & 10812.04 \\ 9/28/2010 & $134.89 & $19.51 & $21.86 & $16.44 & 10858.14 \\ 9/29/2010 & $135.48 & $19.24 & $21.87 & $16.36 & 10835.28 \\ 9/30/2010 & $134.14 & $19.20 & $21.90 & $16.25 & 10788.05 \\ \hline 10/1/2010 & $135.64 & $19.32 & $21.91 & $16.36 & 10829.68 \\ \hline \end{tabular} Closing Stock Prices DJ Industrials Date \begin{tabular}{|r|l|l|l|l|l} & IBM & INTC & CSCO & GE & \multicolumn{1}{l}{ Index } \\ \hline 9/3/2010 & $127.58 & $18.43 & $21.04 & $15.39 & 10447.93 \\ \hline 9/7/2010 & $125.95 & $18.12 & $20.58 & $15.44 & 10340.69 \\ \hline 9/8/2010 & $126.08 & $17.90 & $20.64 & $15.70 & 10387.01 \\ \hline 9/9/2010 & $126.36 & $18.00 & $20.61 & $15.91 & 10415.24 \\ \hline 9/10/2010 & $127.99 & $17.97 & $20.62 & $15.98 & 10462.77 \\ \hline 9/13/2010 & $129.61 & $18.56 & $21.26 & $16.25 & 10544.13 \\ 9/14/2010 & $128.85 & $18.74 & $21.45 & $16.16 & 10526.49 \\ \hline 9/15/2010 & $129.43 & $18.72 & $21.59 & $16.34 & 10572.73 \\ 9/16/2010 & $129.67 & $18.97 & $21.93 & $16.23 & 10594.83 \\ \hline 9/17/2010 & $130.19 & $18.81 & $21.86 & $16.29 & 10607.85 \\ 9/20/2010 & $131.79 & $18.93 & $21.75 & $16.55 & 10753.62 \\ \hline 9/21/2010 & $131.98 & $19.14 & $21.64 & $16.52 & 10761.03 \\ 9/22/2010 & $132.57 & $19.01 & $21.67 & $16.50 & 10739.31 \\ 9/23/2010 & $131.67 & $18.98 & $21.53 & $16.14 & 10662.42 \\ 9/24/2010 & $134.11 & $19.42 & $22.09 & $16.66 & 10860.26 \\ 9/27/2010 & $134.65 & $19.24 & $22.11 & $16.43 & 10812.04 \\ 9/28/2010 & $134.89 & $19.51 & $21.86 & $16.44 & 10858.14 \\ 9/29/2010 & $135.48 & $19.24 & $21.87 & $16.36 & 10835.28 \\ 9/30/2010 & $134.14 & $19.20 & $21.90 & $16.25 & 10788.05 \\ \hline 10/1/2010 & $135.64 & $19.32 & $21.91 & $16.36 & 10829.68 \\ \hline \end{tabular}