sales of Cool-Man air conditioners have grown steadily during the past
five years.

year      sales
----------------
1          450
2          495
3          518
4          563
5          584
6           ?


a)Using a three-year moving average forecasting model to forecast the
sales of Coll-Man air conditioners.

Hi k9queen!!!

A moving average forecast model is based on a time series in which the
value for a given time period is replaced by the mean of that value
and the values for some number of preceding and succeeding time
periods.
Since the forecast value for any given period is an average of the
previous periods, then the forecast will always appear to "lag" behind
either increases or decreases in the past values.
This forescast method is useful when we can assume that market demands
will stay fairly steady over time.

n-period Moving average = Total demand in previous n periods / n .


In this case:

·three-year moving average forecast for year 4:
(450 + 495 + 518)/3 = 487.67

·three-year moving average forecast for year 5:
(495 + 518 + 563)/3 = 525.33

·three-year moving average forecast for year 6:
(518 + 563 + 584)/3 = 555.00

year      sales     3-year Moving Average Forecast    
---------------------------------------------------- 
1          450                 -
2          495                 -
3          518                 -
4          563               487.67
5          584               525.33  
6           ?                555.00


Note that for years 1, 2 and 3 is not possible to use this forecasting
model because we have not 3 previous periods to use in calculations.


I hope this helps you. Feel free to request for any clarification
needed.

Best regards.
livioflores-ga