The table below provides the sales data for JD Inc. for the year 1998. Given:= 0.2,= 0.15, and= 0.05

(Hint: Use an additive Holt-Winters model.)

Umbrella Sales of JD Inc.

Year Month Units

1 Jan 3980

1 Feb 4000

1 Mar 4740

1 April 4720

1 May 4920

1 Jun 5140

1 July 4640

1 Aug 4520

1 Sep 4480

1 Oct 4690

1 Nov 4210

1 Dec 4418

2 Jan 4380

2 Feb 4400

2 Mar 5140

2 April 5120

2 May 5320

2 Jun 5540

2 July 5040

2 Aug 4920

2 Sep 4880

2 Oct 5090

2 Nov 4610

2 Dec 4818

What is the value of the mean absolute deviation for the given data?

A) 340.73

B) 8.10

C) 7.62

D) 14.82

*I have attempted to run this in Excel a dozen times and can't even get close to any of these answers. I'd love to know how to properly input the parameters if you can make it work! I have also tried to work it out by hand...no luck.