The file Quarterly Shipments lists the number of units shipped each quarter for the years 2011–2015 by Bourff Manufacturing.
a. Produce a time-series graph of the data. Are there noticeable trend and seasonal components?
b. Using the Excel 2016 Forecast Sheet option, produce a forecast for each quarter of 2016.
c. Report the smoothing parameters and error measurements produced by Excel’s Forecast Sheet option.
d. Report the 90% confidence interval estimates for the forecast generated.

e. Briefly comment on the forecasting model’s performance.