b$)$ For the forecast developed using exponential smoothing $(=0\mathrm{.}60$ and initial forecast $19\mathrm{.}0),$ the MAD $=5\mathrm{.}83$ sales $($round your response to two decimal places$).$

c$)$ For the forecast developed using exponential smoothing $(=0\mathrm{.}60$ and initial forecast $19\mathrm{.}0),$ the tracking signal $=2\mathrm{.}30($round your response to two decimal places$).$Sales of tablet computers at Marika Gonzalez's electronics store in Washington, D$.$C$.,$ over the past $10$ weeks are shown in the table below: