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hello, I have a question about making n step ahead forecasts in cases where test and validation sets are availiable. For instance, I would like to make one step ahead forecasts on the WWWusage data so I hold out the last 10 observations as the validation set and fit an ARIMA model on the first 90 observations. I then use a for loop to sequentially add 9 of the holdout observations to make 1 step ahead forecasts for the last 10 periods (see example code). In cases where there are relative...

dear members, I have a heteroscedastic time series which I want to transform to make it homoscedastic by a box cox transformation. I am using Otexts by RJ hyndman and George Athanopolous as my textbook. They discuss transformation and also say the fpp3 and the fable package automatically back transforms the point forecast. they also discuss the process which I find to be

Buenos días, Os cuento: Cargo la librería "Forecast" y ejecuto su función Arima(...) sobre una serie temporal: mimodelo <- Arima(miST$miserie, ...); Ahora si ejecuto las siguientes sentencias, voy obteniendo los resultados contenidos en "mimodelo", pero algunos de ellos no sé lo que son: mimodelo[[1]] obtengo los coeficientes del modelo ARIMA mimodelo[[2]] obtengo el

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 My ultimate goal is to best fit time series by comparing AICs and BICs (as in Bayesian) from arima() and nnet(). I looked at the arima.R source code, but I am afraid I do not understand it. What I only miss really is the number of parameters p, where: AIC = n*log(S/n) + 2*p with S the squared residuals and n the number of observations. Can I get p

...l Deaths in the US 1973-1978 USArrests Violent Crime Rates by US State USJudgeRatings Lawyers' Ratings of State Judges in the US Superior Court USPersonalExpenditure Personal Expenditure Data VADeaths Death Rates in Virginia (1940) WWWusage Internet Usage per Minute WorldPhones The World's Telephones ability.cov Ability and Intelligence Tests airmiles Passenger Miles on Commercial US Airlines, 1937-1960 airquality New York Air Quality Measur...

I had a couple of questions about the ar function that i was hoping someone could answer. I have the structure below testSeries<-structure(c(-3.88613620955214e-05, 0, -7.77272551011343e-05, 0, -0.000194344573539562, -0.000116624876218163, -3.88779814601281e-05, 0, 3.88779814601281e-05, -0.000155520995647807, -0.000116656621367561, -3.88885648225368e-05, -3.88900772017586e-05,

...text html latex example UKDriverDeaths text html latex example UKLungDeaths text html latex example UKgas text html latex example USAccDeaths text html latex WWWusage text html latex example acf text html latex example acf2AR text html latex example ar text html latex example ar.ols te...