Freight car loadings over a 12-year period at a busy port are as follows:
a. Determine a linear trend line for expected freight car loadings.
b. Use the trend equation to predict expected loadings for weeks 20 and 21.
c. The manager intends to install new equipment when the volume exceeds 800 loadings per week. Assuming the current trend continues, the loading volume will reach that level in approximately what week?