Displaying 20 results from an estimated 1000 matches similar to: "Problem about SARMA model forcasting"
2011 Sep 09
2
Different results with arima in R 2.12.2 and R 2.11.1
Hello , I have estimated the following model, a sarima:
p=9
d=1
q=2
P=0
D=1
Q=1
S=12
In R 2.12.2
Call:
arima(x = xdata, order = c(p, d, q), seasonal = list(order = c(P, D, Q),
period = S),
optim.control = list(reltol = tol))
Coefficients:
ar1 ar2 ar3 ar4 ar5 ar6 ar7 ar8
ar9
0.3152 0.8762 -0.4413 0.0152 0.1500 0.0001 -0.0413 -0.1811
2010 Nov 22
2
Help: Standard errors arima
Hello,
I'm an R newbie. I've tried to search, but my search skills don't seem
up to finding what I need. (Maybe I don't know the correct terms?)
I need the standard errors and not the confidence intervals from an
ARIMA fit.
I can get fits:
> coef(test)
ar1 ma1
intercept time(TempVector) - 1900
2017 Jun 20
1
How to write an estimated seasonal ARIMA model from R output?
I'm trying to use the following command.
arima (x, order = c(p,d,q), seasonal =list(order=c(P,D,Q), period=s)
How can I write an estimated seasonal ARIMA model from the outputs. To be specifically, which sign to use? I know R uses a different signs from S plus.
Is it correct that the model is:
(1-ar1*B-ar2*B^2-...)(1-sar1*B^s-sar2*B^2s-....)(1-B)^d(1-B^s)^D
2009 Jan 23
1
forecasting error?
Hello everybody!
I have an ARIMA model for a time series. This model was obtained through an
auto.arima function. The resulting model is a ARIMA(2,1,4)(2,0,1)[12] with
drift (my time series has monthly data). Then I perform a 12-step ahead
forecast to the cited model... so far so good... but when I look the plot of
my forecast I see that the result is really far from the behavior of my time
2009 Nov 02
2
using exists with coef from an arima fit
Dear R People:
I have the output from an arima model fit in an object xxx.
I want to verify that the ma1 coefficient is there, so I did the following:
> xxx$coef
ar1 ar2 ma1 intercept
1.3841297 -0.4985667 -0.9999996 -0.1091657
> str(xxx$coef)
Named num [1:4] 1.384 -0.499 -1 -0.109
- attr(*, "names")= chr [1:4] "ar1" "ar2"
2023 Jan 05
1
R 'arima' discrepancies
Rob J Hyndman gives great explanation here
(https://robjhyndman.com/hyndsight/estimation/) for reasons why results
from R's arima may differ from other softwares.
@iacobus, to cite one, 'Major discrepancies between R and Stata for
ARIMA'
(https://stackoverflow.com/questions/22443395/major-discrepancies-between-r-and-stata-for-arima),
assign the, sometimes, big diferences from R
2010 Aug 21
1
How to find residual in predict ARIMA
Dear All,
I have a model to predict time series data for example:
data(LakeHuron)
Lake.fit <- arima(LakeHuron,order=c(1,0,1))
then the function predict() can be used for predicting future data
with the model:
LakeH.pred <- predict(Lake.fit,n.ahead=5)
I can see the result LakeH.pred$pred and LakeH.pred$se but I did not
see residual in predict function.
If I have a model:
[\
Z_t =
2011 Mar 24
1
Problems with predict in fGarch
Hello. I am using fGarch to estimate the following model:
Call:
garchFit(formula = fmla, data = X[, i], trace = F)
Mean and Variance Equation:
data ~ arma(1, 1) + garch(1, 1)
Conditional Distribution:
norm
Coefficient(s):
mu ar1 ma1 omega alpha1 beta1
-0.94934 1.00000 -0.23211 54.06402 0.45709 0.61738
Std. Errors:
based on Hessian
Error Analysis:
2008 Dec 22
2
AR(2) coefficient interpretation
I am a beginner in using R and I need help in the interpretation of AR result
by R. I used 12 observations for my AR(2) model and it turned out the
intercept showed 5.23 while first and second AR coefficients showed 0.40 and
0.46. It is because my raw data are in million so it seems the intercept is
too small and it doesn't make sense. Did i make any mistake in my code? My
code is as follows:
1999 Nov 07
2
arima0() (PR#314)
Full_Name: Ahmad Abu Hammour
Version: rw0651
OS: windows 95
Submission from: (NULL) (63.23.128.44)
Although I know that "ts package" is preliminary, I wanted to compare the
results from R and SPSS. I ran ARIMA(2,1,2) in both softwares. I got NaN in
standard errors of coefficients from R and real figures from SPSS. I changed
"delta" in R to match that used by SPSS, I received
2002 Apr 02
1
predict with arima0
Dear R People:
I'm trying to use the predict command on an arima0 object.
I do the following:
xm.arma <- arima0(xm2,order=c(1,0,1))
predict(xm.arma,n.ahead=2)
and I get the message:
Error in round(x, digits) : Non-numeric argument to mathematical function
Any ideas what the problem might be, please?
R version 1 4 1 on Windows.
Thanks in advance!
Sincerely,
Erin Hodgess
Associate
2005 Oct 13
1
arima: warning when fixing MA parameters.
I am puzzled by the warning message in the output below. It appears
whether or not I fit the seasonal term (but the precise point of doing
this was to fit what is effectively a second seasonal term). Is there
some deep reason why AR parameters
("Warning message: some AR parameters were fixed: ...")
should somehow intrude into the fitting of a model that has only MA
terms?
>
2005 Mar 05
4
How to use "lag"?
Is it possible to fit a lagged regression, "y[t]=b0+b1*x[t-1]+e",
using the function "lag"? If so, how? If not, of what use is the
function "lag"? I get the same answer from y~x as y~lag(x), whether
using lm or arima. I found it using y~c(NA, x[-length(x)])). Consider
the following:
> set.seed(1)
> x <- rep(c(rep(0, 4), 9), len=9)
> y <-
2009 Jun 04
2
Import ARIMA coefficients
Hello,
I need to know how to import ARIMA coefficients. I already determined the coefficients of the model with other software, but now i need to do the forecast in R.
For Example: I have a time series named x
and i have fitted an ARIMA(1,0,1) (with other software)
AR coef = -.172295
MA coef = .960043
(i know that this is not a good model, it's just an example)
I try to
2011 Aug 30
2
ARMA show different result between eview and R
When I do ARMA(2,2) using one lag of LCPIH data
This is eview result
>
> *Dependent Variable: DLCPIH
> **Method: Least Squares
> **Date: 08/12/11 Time: 12:44
> **Sample (adjusted): 1970Q2 2010Q2
> **Included observations: 161 after adjustments
> **Convergence achieved after 14 iterations
> **MA Backcast: 1969Q4 1970Q1
> **
> **Variable Coefficient Std.
2012 Nov 14
0
ARIMA\GARCH forcasting
Hi,
I am new to using R and time series analysis in general. I have written code
to combine ARIMA + GARCH in forcasting. I am finding it hard to actually
get predicted values once I have model built and fit it to data series. i.e.
how can I use predict function to give me n.ahead = k number of values.
Thanks in advance,
Vinay
--
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2013 Feb 11
1
assign estimated values
Hi,
I want to assign the ar1 , ma 1 and the intercept estimated by the
following<http://r.789695.n4.nabble.com/assign-estimated-values-td4658138.html#>code
to three variables a, b and c respectively.
Can anyone help me with this please?
code:
a0 = 0.05; a1 = 0.1; b1 = 0.85
nu = rnorm(2500)
epsi = rep(0, 2500)
h = rep(0, 2500)
for (i in 2: 2500) { h[i] = a0 + a1 * epsi[i-1]^2 + b1 * h[i-1]
2006 Nov 23
1
ARMAX Models in R
Hi,
I want to model different timeseries with ARMAX models in R because I think
that ARMAX models will map best to these data.
Besides I don't want to use the order of the AR or MA part but the lag e.g.
AR Part =ar1, ar2, ar7; MA Part =ma1, ma3 and I want to use exogenous
variables as well.
I coudn't find any solutions in the R help and therefore I want to ask all
of you.
Does anyone
2006 Jun 01
1
why does arima returns "NAN" standard error?
Hi everyone,
-----------------------------
Coefficients:
ar1 ar2 ma1 ma2 sar1 intercept drift
1.5283 -0.7189 -1.9971 0.9999 0.3982 0.0288 -9e-04
s.e. 0.0869 0.0835 0.0627 0.0627 0.1305 NaN NaN
sigma^2 estimated as 0.04383: log likelihood = 4.34, aic = 7.32
Warning message:
NaNs produced in: sqrt(diag(object$var.coef))
2013 Jun 07
1
arima time series in R
Hi
Could just anyone explain me the coefficients in the output of arima model
timeseriesarima <- arima(series, order=c(1,1,2))
> timeseriesarima
Series: series
ARIMA(1,1,2)
Coefficients:
ar1 ma1 ma2
0.9744 -1.7695 0.7873
s.e. 0.0310 0.0481 0.0426
sigma^2 estimated as 337.4: log likelihood=-1096.03
AIC=2200.07 AICc=2200.23 BIC=2214.2
****************