Johns Crab Shack sells crabs to restaurants in Maine the dat
John\'s Crab Shack sells crabs to restaurants in Maine, the data below is sales over a three year period.
The Owner wants to forecast the number of sales for January 2013. He wants to use a 5 period moving average smoothing model to arrive at the forecast.
a) Provide the desired forecast for Period 37 based on the Moving Average Soothing Model
B) Calculate the MAD value for this linear trend model
| Year | Month | Month Number | Sales Received | 
| 2010 | Jan | 1 | 23,500 | 
| Feb | 2 | 21,700 | |
| Mar | 3 | 18,750 | |
| Apr | 4 | 22,000 | |
| May | 5 | 23,000 | |
| Jun | 6 | 26,200 | |
| Jul | 7 | 27,300 | |
| Aug | 8 | 29,300 | |
| Sep | 9 | 31,200 | |
| Oct | 10 | 34,200 | |
| Nov | 11 | 39,500 | |
| Dec | 12 | 43,400 | |
| 2011 | Jan | 13 | 23,500 | 
| Feb | 14 | 23,400 | |
| Mar | 15 | 21,400 | |
| Apr | 16 | 24,200 | |
| May | 17 | 26,900 | |
| Jun | 18 | 29,700 | |
| Jul | 19 | 31,100 | |
| Aug | 20 | 32,400 | |
| Sep | 21 | 34,500 | |
| Oct | 22 | 35,700 | |
| Nov | 23 | 42,000 | |
| Dec | 24 | 42,600 | |
| 2012 | Jan | 25 | 31,000 | 
| Feb | 26 | 30,400 | |
| Mar | 27 | 29,800 | |
| Apr | 28 | 32,500 | |
| May | 29 | 34,500 | |
| Jun | 30 | 33,800 | |
| Jul | 31 | 34,200 | |
| Aug | 32 | 36,700 | |
| Sep | 33 | 39,700 | |
| Oct | 34 | 42,400 | |
| Nov | 35 | 43,600 | |
| Dec | 36 | 47,400 | 
Solution
For a 5 period moving average previous 5 months avrage is calculated
ie.average for Aug, Sep, oct, nov and dec is forecast for Jan 2013
= 41960
a) Moving average soothing model = average of all = 31763
c) MAD value for this linear trend is Mean absolute deviation.


