I am really stuck and need help with figuring this question out or if
you can guide where I can go to get directions, your assistance is
greatly appreciated.  I need to have this answered by Monday, April
19th. Thank you.

Here is the question:
"Using the classical decomposition method, calculate the seasonal
ratios from the data, and determine the trend and average levels.  Use
these ratios and estimates of trend and level to make a forecast for
the next year."

You will need to use the following chart to calculate the seasonal ratios.

Month       Year 1 Demand    Year 2 Demand   Year 3 Demand   Seasonal Ratio
Jan           $12,400           $11,800        $13,600          0.8
Feb            23,000            24,111         21,800          1.8
Mar            15,800            16,500         14,900          0.9
Apr            20,500            21,000         19,400          1.6
May            25,100            24,300         26,000          2.0
June           16,200            15,800         16,500          1.0
July           12,000            11,500         12,400          0.7
Aug            10,300            10,100         10,800          0.6
Sept           11,800            11,000         12,500          0.7
Oct            14,000            14,300         13,800          1.2
Nov            10,700            10,900         10,600          0.9
Dec             7,600             7,200          8,100          0.6

---

Request for Question Clarification by livioflores-ga on 18 Apr 2004 20:57 PDT

Hi!!

I have not enough skills to do this exercise, but as you requested I
found two documents that will give you some guidance.
If they help you to do this task, let me know and I will post them in
the answer box so I can claim the price.

"Classical Decomposition":
This is a Powerpoint document, you have an example and a good
explanation in there. Theory includes slides 1 to 17 inclusive. The
sample exercise (with step by step explanation) starts at slide 18.
Download this PPT from:
http://www.freequality.org/beta%20freequal/fq%20web%20site/Training/Classes%20Spring%202003/PowerPoint%20Slides/Classical%20Decomposition.ppt


"Forecasting":
This entire page will be helpful to you, here you will find this
method described and a sample problem with solution (follow the 'Web:
Housing Sales Data' and 'Web: International Airline Data' links to see
the tables).
http://www.maths.soton.ac.uk/teaching/units/ma620/ForecastingChap2.htm


I hope this helps you. I will wait for your feedback to post the
answer or to continue the research.

Regards.
livioflores-ga