Answer: A$)$ Chart A is the correct choice for the given data. The data is presented in a time series format, where each data point represents the sales of business textbooks for a specific year. The time series plot shows a general upward trend in sales over the eight$-$year period, with some fluctuations and variations. The data points are connected by a line, which helps to visualize the trend and relationships between the data points.B$)$ The formula for calculating the forecast error is:Forecast Error $=$ Actual Sales $-$ Forecasted SalesC$)$ To construct the $2$s control limits$,$ we need to calculate the average of the forecast errors over the eight years. The average forecast error is:Average Forecast Error $=($Error$1+$ Error$2+$ Error$3+$ Error$4+$ Error$5+$ Error$6+$ Error$7+$ Error$8)/8$ Average Forecast Error $=(40\mathrm{.}30-43\mathrm{.}20+47\mathrm{.}70-50\mathrm{.}70+54\mathrm{.}20-57\mathrm{.}30+63\mathrm{.}00-69\mathrm{.}90)/8$ Average Forecast Error $=44\mathrm{.}78$The $2$s control limits are calculated using the average forecast error and a value of $2.$ The control limits are:Upper Control Limit $($UCL$)=$ Average Forecast Error $+(2*$ Average Forecast Error$)$ Upper Control Limit $=44\mathrm{.}78+(2*44\mathrm{.}78)$ Upper Control Limit $=99\mathrm{.}56$Lower Control Limit $($LCL$)=$ Average Forecast Error $-(2*$ Average Forecast Error$)$ Lower Control Limit $=44\mathrm{.}78-(2*44\mathrm{.}78)$ Lower Control Limit $=44\mathrm{.}78-99\mathrm{.}56$ Lower Control Limit $=-54\mathrm{.}78$Therefore, the $2$s control limits for the forecasting process are:Upper Control Limit $=99\mathrm{.}56$ Lower Control Limit $=-54\mathrm{.}78$D$)$ The forecast errors for years $9$ to $13$ are:Forecast Error$9=74\mathrm{.}70-99\mathrm{.}56$ Forecast Error$9=-24\mathrm{.}86$Forecast Error$10=78\mathrm{.}50-99\mathrm{.}56$ Forecast Error$10=-21\mathrm{.}06$Forecast Error$11=82\mathrm{.}90-99\mathrm{.}56$ Forecast Error$11=-16\mathrm{.}66$Forecast Error$12=87\mathrm{.}40-99\mathrm{.}56$ Forecast Error$12=-12\mathrm{.}06$Forecast Error$13=92\mathrm{.}90-99\mathrm{.}56$ Forecast Error$13=-6\mathrm{.}56$The forecasting process is not in control, as the actual sales for years $9$ to $13$ are outside the control limits$.$ The forecast errors are consistently negative, indicating that the model is not accurately predicting the sales trend. This suggests that the model needs to be adjusted or improved to better capture the underlying trends and relationships in the data. Final answer: The correct answer is: A$)$ Chart A B$)$ Forecast Error $=$ Actual Sales $-$ Forecasted Sales C$)$ Upper Control Limit $=99\mathrm{.}56$ Lower Control Limit $=-54\mathrm{.}78$ D$)$ Forecast Error$9=-24\mathrm{.}86$ Forecast Error$10=-21\mathrm{.}06$ Forecast Error$11=-16\mathrm{.}66$ Forecast Error$12=-12\mathrm{.}06$ Forecast Error$13=-6\mathrm{.}56$ The forecasting process is not in control