Displaying 20 results from an estimated 40000 matches similar to: "question about order selection of ar"
2011 Mar 29
1
Simple AR(2)
Hi there, we are beginners in R and we are trying to fit the following time
series using ar(2):
> x <- c(1.89, 2.46, 3.23, 3.95, 4.56, 5.07, 5.62, 6.16, 6.26, 6.56, 6.98,
> 7.36, 7.53, 7.84, 8.09)
The reason of choosing the present time series is that the we have
previously calculated analitically the autoregressive coefficients using
the direct inversion method as 1.1, 0.765, 0.1173.
2009 Nov 13
2
AR(2) modelling
Hi useRs,
I'm trying to fit a basic AR(2) model with the 'ar' function. And when
I try to check the value of the coefficients, I could not find the
same value as the 'ar' function.
Here is my example:
myserie <- c(212, 205, 210, 213, 217, 222, 216, 218, 220, 212, 215, 236)
#plot(myserie, type="l")
myserieminus0 <- tail(myserie, -2)
myserieminus1 <-
2009 Nov 13
2
AR(2) modelling
Hi useRs,
I'm trying to fit a basic AR(2) model with the 'ar' function. And when
I try to check the value of the coefficients, I could not find the
same value as the 'ar' function.
Here is my example:
myserie <- c(212, 205, 210, 213, 217, 222, 216, 218, 220, 212, 215, 236)
#plot(myserie, type="l")
myserieminus0 <- tail(myserie, -2)
myserieminus1 <-
2011 Oct 19
1
ar() - AIC and BIC
Hi,
I'm slowly working through Tsay's "Analysis of Financial Time Series"
3rd ed. ?I'm trying to replicate Table 2.1 on p.47, which gives PACF,
AIC, and BIC for the monthly simple returns of the CRSP value-weighted
index.
The data:
http://faculty.chicagobooth.edu/ruey.tsay/teaching/fts3/m-ibm3dx2608.txt
> da <-
2011 Dec 01
1
combining arima and ar function
Hi everyone
I've got a problem regarding the arima() and the ar() function for
autoregressive series. I would simply like to combine them.
To better understand my question, I first show you how I'm using these two
functions individually (see file in the attachement).
1) apply(TSX,2, function(x) ar(na.omit(x),method="mle")$order
# this function finds the optimal
1999 Jul 19
9
time series in R
Time Series functions in R
==========================
I think a good basic S-like functionality for library(ts) in base R
would include
ts class, tsp, is.ts, as.ts
plot methods
start end window frequency cycle deltat
lag diff aggregate
filter
spectrum, spec.pgram, spec.taper, cumulative periodogram, spec.ar?
ar -- at least univariate by Yule-Walker
arima -- sim, filter, mle, diag, forecast
2000 Jun 20
1
pacf
Dear list,
according to the documentation of acf{ts}
"the partial correlation coefficient is estimated by fitting
autoregressive models of successively higher orders up to lag.max. "
However, R seems to return the Yule-Walker estimates of the PACF by
default. You can check this using c(1:10) as the series: the YW
estimates are 0.7000000 and -0.1527035 for lags 1 and 2 . If the PACF
2006 Nov 13
1
bug in acf (PR#9360)
Full_Name: Ian McLeod
Version: 2.3.1
OS: Windows
Submission from: (NULL) (129.100.76.136)
> There is a simple bug in acf as shown below:
>
> z <- 1
> acf(z,lag.max=1,plot=FALSE)
> Error in acf(z, lag.max = 1, plot = FALSE) :
> 'lag.max' must be at least 1
>
This is certainly a bug.
There are two problems:
(i) the error message is wrong since lag.max is
2011 Jan 17
0
Fw: Re: help in calculating ar on ranked vector
--- On Mon, 1/17/11, Raymond Wong <raywong365@yahoo.ca> wrote:
From: Raymond Wong <raywong365@yahoo.ca>
Subject: Re: [R] help in calculating ar on ranked vector
To: "Uwe Ligges" <ligges@statistik.tu-dortmund.de>
Received: Monday, January 17, 2011, 11:56 AM
Thanks Uwe:
Here is my code. the first set of print statements work, but not the second.
#
2003 Jun 19
1
What's wrong with ar for my data?
Dear helpers,
When I use ar to fit the data with length 180, I have the following
error:
ar(x,method="burg")
Error in acf(x, type = "covariance",lag.max=order,plot=FALSE):
lag.max must be at least 1
If I use
ar(x), then I have
Call (x=x)
order selected 0 sigma^2 estimated as 5374
Obviously I missed some points for using ar.
This is R 1.7.0 under Redhat Linux
2007 Aug 31
3
Choosing the optimum lag order of ARIMA model
Dear all R users,
I am really struggling to determine the most appropriate lag order of ARIMA model. My understanding is that, as for MA [q] model the auto correlation coeff vanishes after q lag, it says the MA order of a ARIMA model, and for a AR[p] model partial autocorrelation vanishes after p lags it helps to determine the AR lag. And most appropriate model choosed by this argument gives
2008 Jun 01
2
how to analyze time series structures?
h?, I am preparing undergraduate thesis If you help me this would make me
feel good.
First I need to analyze effect of Dow Jones Industrial average(DJIA)'s
return on Istanbul Stock Exchange(ISE). I want to use Markov-Switching
Bayesian Vector Autoregression Models (MSBVAR) that is used to examine the
effect of a large economy?s stock exchange movement on a small economy?s
stock exchange
2008 Apr 24
0
Coefficient of determination in a regression model with AR(1) residuals
Dear R-users,
I used lm() to fit a standard linear regression model to a given data
set, which led to a coefficient of determination (R^2) of about
0.96. After checking the residuals I realized that they follow an
autoregressive process (AR) of order 1 (and therefore contradicting
the i.i.d. assumption of the regression model). I then used gls()
[library nlme] to fit a linear
2011 Jul 07
3
AR vs ARIMA question
Dear R People:
Here is some output from AR and ARIMA functions:
> xb <- arima.sim(n=120,model=list(ar=0.85))
> xb.ar <- ar(xb)
> xb.ar
Call:
ar(x = xb)
Coefficients:
1
0.6642
Order selected 1 sigma^2 estimated as 1.094
> xb.arima <- arima(xb,order=c(1,0,0),include.mean=FALSE)
> xb.arima
Call:
arima(x = xb, order = c(1, 0, 0), include.mean = FALSE)
1999 Jul 27
3
Preliminary version of ts package
There is now a preliminary version of a time series package in the R-devel
snapshots, and we would welcome feedback on it. It is based in part on the
packages bats (Martyn Plummer) and tseries (Adrian Trapletti) and in part
on code I had or have written. (Thanks for the contributions, Martyn and
Adrian!) Some of the existing ts code has been changed, for example to plot
multiple time series, so
2011 Nov 17
3
R help
Hello:
I have some trouble making a prediction from an AR(p) model. After I have the AR(p) model fitted , I want to use a new data set to make predictions.
But I get the error: Error in newdata - object$x.mean : non-numeric argument to binary operator.
A small version of my original data looks like:
X1
X2
X3
X4
40813.65
1
10
41.86755
40813.65
1
8
41.86755
40813.66
1
8
41.86755
2013 Apr 14
2
ZA unit root test lag order selection
I was wondering if anyone could help with choosing optimal lag length for ZA
test.
There have been two lag order selection methods commonly used in the
literature:
1) The ZA paper recommends to run the test with maximum number of lags. Then
the lag order is reduced sequentially until the longest lag is statistically
significant;
2) One could also use AIC or SBC or other criteria to choose lag
2006 Oct 24
0
samba becomes unreliable on upgrading to SOlaris 10
Hello,
we've been more than happy with Samba 3.0.22 on our Solaris 9 machines,
but when we upgraded to Solaris 10 users are experiencing a multitude
of XP desktop problems: icons disappear, start menu will hang because a
few items link back to a samba share, many XP windows write delay
problems, the whole desktop will hang. It seems the samba server will stop responding.
Is there anybody out
2009 Jun 02
1
plot 4th variable contour lines on filled.contour
Hello,
I have a dataset with 4 variables, each consisting of a vector, all with
the same length. I start by interpolating the first three variables
using the function "interp", and plot the interpolation successfully
using "filled.contour". I then interpolate the first two variables and a
fourth using "interp" again, but when I try to overlay the contour
lines
2011 Oct 28
1
Quotas with Maildir and mdbox
Hello,
We use LDAP to store our Maildir++ quota information for our Maildir
mailboxes. I notice in the documentation that only SQL and flat files
are supported by the dictionary quota if I want to use quota with mdbox?
Are there any plans to allow LDAP to be used as the store?
Regards,
Matthew.
--
Dr Matthew Williams MEng PhD MBCS
Systems Administrator - IT Services - Bangor