Good after noon sir
the following data represents a time series:
x 36 y 41 34 38 42
a series of three points moving average 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?
a)38,39 b)38,40 c)40,38 d)39,38
sir i have seen the solution to this but still cant get through can you please explain Thank you
Ask the Tutor ACCA MA
Forecasting
10y ago
10y ago#1X and Y are the missing figures in the list.
Because it is a 3 point moving average, the averages are the averages of 3 items at a time.
So......(X + 36 + Y ) / 3 = 38
or (multiplying everything by 3)
X + 36 + Y = 114
For the second average,
(36 + Y + 41) / 3 = 39
or (multiplying everything by 3)
36 + Y + 41 = 117
So Y = 117 - 36 - 41 = 40.
(In the exam you would stop here, because only one of the choices has Y = 40 :-) )
However, going back to the first equation, we now know that:
X + 36 + 40 = 114
So X = 114 - 36 - 40 = 38
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