Won Problem 3-7 (Static) Freight car loadings over an 18-week period at a busy port are as follows: WeekNumber 1 220 2 245 3 280 4 275 5 389 310 Week 7 7 8 9 10 11 12 Number 350 360 400 389 428 450 Week Number 13 460 14 475 15 500 16 510 17 525 18 541 Click here for the Excel Data File ns a. Determine a linear trend line for expected freight car loadings. (Round your intermediate calculations and final answers to 2 decimal places.) YE b. Use the trend equation to predict expected loadings for weeks 20 and 21. (Round your final answers to 2 decimal places.) The forecasted demand for week 20 and 21 and respectively c. The manager intends to install new equipment when the volume exceeds 800 loadings per week. Assuming the current trend c. continues, the loading volume will reach that level in approximately how many more weeks? (Use the rounded answers, as required, from any previous part of this problem. Do not round any other intermediate calculations. Round your final answer to 2 decimal places.) it would take approximately more weeks