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Time series

Rrkwasim11y ago
Hey John, Could you help me out to solve following question. Thanks 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? A (38, 39) B (38, 40) C (40, 38) D (39, 38)
John MoffatJohn MoffatTutor11y ago#1
Where did you find this question? And if you have the question why do you not have the answer? As it is written, the question makes no sense at all. Everything you need for the exam on time series (and on all the topics) is covered in our free lectures.
Rrkwasim11y ago#2
Hey John, Thanks for quick reply but this question is in BPP exam kit chapter 14. Following is the answer on book. X = 38 and Y = 40 X + 36 + Y = 38 3 36 + Y + 41 = 39 3 Y = (3 × 39) – 36 – 41 = 40 X + 36 + 40 = 38 3 X = (38 × 3) – 36 – 40 = 38
John MoffatJohn MoffatTutor11y ago#3
Well it still seems a remarkably silly question to me :-)
Rrkwasim11y ago#4
Thanks John for your help.
John MoffatJohn MoffatTutor11y ago#5
You are welcome :-) (although I was not much help!!)
AAayisha10y ago#6
Hello Sir! Can you please help me out with the question 1 of test from chapter 19 which is related to time series. Thank You! Question for your reference: In a time series analysis, the additive model is used to forecast sales and the following seasonal variations apply: Quarter 1 2 3 4 Seasonal variation: +5.8 -8.4 +10.2 ? The seasonal variation for quarter 4 is: A +7.6 B -8.1 C -7.6 D +8.1
John MoffatJohn MoffatTutor10y ago#7
Two things: Firstly, the answers are at the end of the lecture notes. Secondly, I do suggest that you watch the free lecture. You will find there that the seasonal variations must add up to zero (if using the additive model). Therefore since we know three of them, then the fourth must be whatever makes all four add up to zero. (The notes are not meant to be used without the lectures. It is in the lectures that we explain and expand upon the notes.)
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