$>9\mathrm{.}323.$ Cynthia's Design Studios had sales the last four months of $$13,700,$ $$15,400,$ $$17,100,$ and $$18,800.$ Sales are related to how many designers Cynthia has on$-$duty. The sales forecast helps her decide on the proper staffing levels. a$.$ What is the forecast for the fifth month using a two$-$period moving average? b$.$ What is the forecast for the fifth month using a $=0\mathrm{.}9$ in an exponential smoothing model with A$,==$ $$18,800$ and F$.=$ $$16,913$ to get things started. $==$