Mountain Aquaculture and Producers Association (MA&PA) is a small trout producers€™ cooperative in West Virginia.13 Its main product is boned, head-removed trout sold to local stores. One of the problems MA&PA is facing is that the demand for its products is seasonal (see the sales in pounds of boned, head-removed trout from Q1 1997 to Q3 2000 below). The manager would like to plan production better.

a. Compute the seasonal relative for each quarter using the centred moving average method.
b. Deseasonalize the data, fit an appropriate model to the deseasonalized data, extend the model four quarters, and reseasonalize these in order to forecast the sales of boned, head- removed trout from the 4th quarter of 2000 to 3rd quarter of 2001.

Year 1997 1999 1999 2000 Q1 664 422 803 698 Q2 1,338 1,098 1,430 1,076 Q3 1,170 1,939 1,206 1,149 Q4 259 1,069 843