Freight car loadings over an 18-week period at a busy port are as follows: Week Number Week Number Week Number 123+ 320 7 390 13 425 335 8 400 14 435 350 9 410 15 465 4 335 10 395 16 480 56 5 350 11 405 17 495 360 12 415 18 510 Click here for the Excel Data File a. Determine a linear trend line for expected freight car loadings. (Round your intermediate calculations and final answers to 2 decimal places.) = t b. Use the above trend equation to predict expected loadings for Weeks 20 & 21. (Round your final answers to 2 decimal places.) The forecasted demand for Week 20 is and for Week 21 is c. The manager intends to install new equipment when the volume exceeds 900 loadings per week. Assuming the current trend continues, in which week (at the earliest) should the loading volume reach that level? (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 should reach 900 loadings in Week