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So this trend ( the average per period) is the same thing as the moving average?
The seasonally adjusted figure is also called the trend or centered average and this figure of 4300 is also stated as trend in the question. So what is the difference?
@czxy said:
Question: The following data represents a time series:X 36 Y 41 34 38 42
A series of three point moving averages produced from this data has given the first two values as 38 and 39. What are the values of (X,Y) in the original time series?
Why the question states three point moving averages, it should be four point moving averages if moving averages are calculated quarterly not 1/3 of a year. Also the question asks for the original time series but a time series is already given in the quesiton. So what is the difference between the time series given in the question and the original time series? I can not grasp the point of the question and how to approach it.
@czxy said:
Question: Unemployment numbers actually recorded in a town for the second quarter of the year 2000 were 4700. The underlying trend at this point was 4300 people and the seasonal factor is 0.92. Using the multiplicative model for seasonal adjustment, what is the seasonally-adjusted figure (in whole numbers) for the quarter?In the book the answer is simply given as 4700/0.92, but why is actual amount 4700 not multiplied by 0.92 to get the forecast trend — why is the process in reverse?
Also why the seasonal factor is 0.92? It should be 4700/4300 and then multiplied by 100 which is equal to 109.3%. And so the forecast trend should have been calculated as 4700/1.09. Why this is not the case and what is the relationship between 4700 and 4300?