5. Monthly watch sales at a large retail store are reported in the excel le.

(a) [10] Present an excel spreadsheet detailing a double Holt-Winters exponential

smoothing for these sales. Use it to nd point and interval prediction for the next

month. Provide point forecast for months 21 through 26.

(b) [5] Use minitab to do the same work in above in (a).

See attached image for Excel data

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