Use regression analysis to fit a linear trend model to the data set. (a) What is the estimated regression function? (Use t for X, where t = 1, 2, .... Round your numerical values to four decimal places.) = 322.3807 + 11.4965X (b) Interpret the R2 value for your model. (Give your answer as a percent. Round your answer to one decimal place.) Approximately 91.9 % of the total variation in sales is accounted for by the model. (c) Prepare a line graph comparing the linear trend predictions against the original data. 600r 600r O Sales (in $1,000) Sales (in $1,000) 550 500 450 400 350 300 250 0 600r 550 500 450 400 X 350 5 10 Year Sales Forecast 15 Sales 20 Sales (in $1,000) Sales (in $1,000) 550 500 450 400 350 300 250 0 600 550 500 450 400 350 5 10 Year Sales Forecast 15 Sales Forecast 20