Sales of Volkswagen's popular Beetle have grown steadily at auto dealerships in Nevada during the past $5$ years $($see table below$).$

a$)$ Forecasted sales for year $6$ using the trend projection $($linear regression$)$ method are $|$ sales $($round your response to one decimal place$).$

b$)$ What is the MAD for a linear regression forecast is$?$ sales $($round your response to one decimal place

c$)$ What is MSE for the linear regression forecast is$?$