Refer to the data in the file that accompanies this book named ChemicalDemand.xlsx containing monthly data on the demand for a chemical product over a 2 year period.

Use the additive seasonal technique for stationary data to model the data. Use Solver to determine the optimal values of a and b.

a. What are the optimal values of a and b?
b. Prepare a line graph comparing the predictions from this method against the original data.
c. What are the forecasts for the next 4 months using this technique?