This question is surely trivial, sorry. I'm afraid I'm misunterpreting
the information I got with the documentation, and I'm a little bit
confused. I'm just an engineer with some little skills in statistics.
Well, I have a time series - 600 days long - with some weekly
periodicity inside. So far, so good.
Well, if I define the time series with, say :
a <- ts(b, frequency = 7)
and I do "plot(a)", each unit of time seems to be a week, not a day,
which is coherent with help(ts) which says "frequency: the number of
observations per unit of time." but this isn't what I want. I'd like to
retrieve seasonal information but, as I'd like to retrieve also day to
day information, the time unit should remain one "day".
Also, when I use the "arima(...)" function to fit a model (almost the
same kind of algorithm which appeared here some days ago), and I specify
in the "seas=" parameter, "frequency = 7", or "frequency = frequency(a)"
(a is the time series), I can get arN, maN, sarN, smaN... coefficients.
What unit shall be applied to these coefficients ? One day or one week ?
Logically (and ideally), for me, one day for arN and maN and one week
for sarX and smaX coefficients, but I'm not sure.
I have the same kind of doubt about lag units when I apply the acf()
function to the time series (a) or the residuals returned by the arima()
function.
Thanks for your answer.
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
