Displaying 20 results from an estimated 4000 matches similar to: "header containing (PR#8231) -- replace 8231"
2005 Oct 21
0
Error in arima reporting (PR#8231)
When arima is used to fit a time series, the output gives an
estimate of the mean of the series, but calls it the intercept.
For example, if x(t) = a + b x(t-1) + w(t) is a stationary AR(1)
and w(t) is white noise, then mu = a + b mu, or a = mu (1-b),
where mu = E(x(t)). Unless b=0, the mean mu and the intercept a
are not the same. Here's a quick R example:
> x =
2006 Apr 03
0
Problems with arima function (PR#8743)
I have written before, but to no avail. I have found two minor
problems with fitting time series models with R. The thing is, they
may be solved with MINOR adjustments to the code.
I have posted these problems with detailed examples here:
http://www.stat.pitt.edu/stoffer/tsa2/Rissues.htm
Briefly, the problems are
(1) When fitting time series models when there is an AR term present,
the
2007 Jan 02
1
arith-true mean() fails make check on IRIX
Hello,
I am building R-2.4.1 on an SGI IRIX platform, using gcc 3.3.
gmake check failed, and the arith-true.Rout.fail file indicated:
> is.na(mean(c(1,NA,NA)[-1], trim = .1, na.rm = TRUE))
[1] FALSE
>
I tried the mean() command in R and got:
> mean(c(1,NA,NA)[-1], trim = .1, na.rm = TRUE)
[1] Inf
I think the problem is in the na.rm = TRUE, because I get:
> mean(c(1,NA,NA)[-1])
[1]
2009 Feb 25
1
Problems with ARIMA models?
Dear R,
I have find a website where they report problem with ARIMA models in R. I
run the examples there and they give result as shown on the website. Does
this mean that nothing has corrected in R? Maybe you not have seen the
page, but the author said he contacted you.
Here is the URL: http://www.stat.pitt.edu/stoffer/tsa2/Rissues.htm
I like to know your opinion.
Mvh.
Marie
[[alternative
2009 Feb 25
1
Problems with ARIMA models?
Dear R,
I have find a website where they report problem with ARIMA models in R. I
run the examples there and they give result as shown on the website. Does
this mean that nothing has corrected in R? Maybe you not have seen the
page, but the author said he contacted you.
Here is the URL: http://www.stat.pitt.edu/stoffer/tsa2/Rissues.htm
I like to know your opinion.
Mvh.
Marie
[[alternative
2009 Mar 05
3
Time Series - ARIMA differencing problem
Hi,
I have been using this website (
http://www.stat.pitt.edu/stoffer/tsa2/Rissues.htm
http://www.stat.pitt.edu/stoffer/tsa2/Rissues.htm ) to help me to fit ARIMA
models to my data. At the moment I have two possible methods to use.
Method 1
If I use
arima(ts.data, order=c(1,2,0), xreg=1:length(ts.data))
then the wrong value for the intercept/mean is given (checked on SPSS and
Minitab) and
2006 Jul 21
1
Failed to set servicePrincipalNames (Samba+Solaris 10+NISplus+ADS+DNS)
When joining our Solaris 10 Samba 3.0.23 system to ADS via...
# /usr/local/samba/bin/net ads join -U Administrator
Administrator's password:
Using short domain name -- ULS
Failed to set servicePrincipalNames. Only NTLM authentication will be
possible.
Please ensure that the DNS domain of this server matches the AD domain,
Or rejoin with using Domain Admin credentials.
Joined
2009 Mar 26
1
arima, xreg, and the armax model
Hello all,
I''m having fun again with the arima function. This time I read in:
http://www.stat.pitt.edu/stoffer/tsa2/R_time_series_quick_fix.htm
<<It has recently been suggested (by a reliable source) that using xreg in
arima() does NOT fit an ARMAX model [insert slap head icon here]. This will
be investigated as soon as time permits.>>
(by R.H. Shumway & D.S. Stoffer)
2006 Jan 05
1
Memory limitation in GeoR - Windows or R?
Dear Aaron,
I am really a tool user and not a tool maker (actually an ecologist
doing some biostatistics)... so, I take the liberty of sending a copy of
this e-mail to the r-help list where capable computer persons and true
statisticians may provide more relevant information and also to Paulo
Ribeiro and Peter Diggle, the authors of geoR..
I really feel that your huge matrix cannot be
2008 Jan 14
1
savehistory in OSX version
Running Version 2.6.0 GUI 1.21.
Generally, I enjoy working with the OSX GUI,
which has some very pleasant features.
Kudos to the developers!
There is a nice history panel which slides out of the
Console window. The buttons on the panel work as expected.
I am puzzled by the behavior of history() and savehistory()
run from the Console window. I would think that these functions
would view and
2010 Jun 01
1
mvbutils and trackObjs
Hello Colleagues,
I've recently become a fan of Mark Bravington's mvbutils package for organizing analysis projects in a tree.
Using cd(), Save(), fixr(), mlazy() etcetera solves nicely some of the nuisances that have worried or annoyed me and sometimes caused
big problems over the years. Well thought out.
Now one feature that would be fabulous would be automatic time-stamping of
2008 Jan 14
1
a way to interrupt a stuck R session on OSX
Discovered by accident:
If your R session has become unresponsive to escape presses etcetera,
you can try this.
Open a terminal window, run the command
ps -ax | grep R.app
Note the process ID number in the first column. Say it's 1234.
Then run
kill -4 1234
The key is that the signal you are sending to R.app is "4".
The Console will now ask you how you want to exit.
This
2010 Jan 30
2
question about time series objects
Hi All,
I have a very simple question about a time series object: how to access
values for a particular year and quarter (say)?
Suppose, following
http://www.stat.pitt.edu/stoffer/tsa2/R_time_series_quick_fix.htm
I have read in data as a time series; here is how it looks.
* Qtr1 Qtr2 Qtr3 Qtr4
1960 0.71 0.63 0.85 0.44
1961 0.61 0.69 0.92 0.55
. . . . .
2009 Nov 09
0
ARIMA, xreg and intercepts
David Stoffer describes some challenges with R's output when fitting
ARIMA models for different orders (see Issue 2 at
http://www.stat.pitt.edu/stoffer/tsa2/Rissues.htm). R doesn't fit an
intercept in the model if there is any differencing. David describes a
workaround using the xreg parameter to force R to calculate an
intercept.
Assume I have a variable y and 3 explanatory variables a,
2008 Mar 26
2
pseudo R square and/or C statistic in R logistic regression
Dear all,
I am now doing the logistic regression using R. (glm, family=binomial). Besides the standardize summary statistics generated from R, I am also interested in some more informations concerning the model fitting / prediction etc; Particularly I am interested in "pseudo R squar" and "C statistic". I searched the R- help and could only get very limited information. (Post
2009 Oct 28
3
structural equation modeling
Dear R-help,
I am interested in using structural equation modeling.
Just getting started with it, but I'm looking for suggestions for packages.
As an aside, what's the best way for looking for packages at CRAN?
--
Robert Terwilliger
Biomedical Physicist
Laboratory of Neurocognitive Development
Western Psychiatric Institute and Clinic
University of Pittsburgh Medical Center
Loeffler
2006 Sep 27
1
MSM modeling and transition rates in R
Greetings,
I'm using MSM (mutli-state markov modeling) package to study the
progression of fibrosis in U.S hepatitis C population. I find this is a
very fascinating tool for an applied researcher like myself.
I have a four stage progression only model without any absorbing stage,
also assuming no misclassification error in the data for the time being.
I also have a couple covariates in the
2006 Nov 06
1
simple random cluster sampling - bootstrapping
Hello all,
I have 300 clusters of fixed size 2 and I need to do resampling with
replacement to run some regression models. I've searched through the
archive and the only thing I found was that I could use 'boot()'
function. but it's not clear to
me how I can do this. Has anyone done it? I would very much appreciate
your help,
kelly
2009 Oct 23
1
making a plot in xyplot
Hello,
I am a newbie to the lattice package in R, and I'm trying to make a plot using the xyplot function. I have repeated measures data (2 conditions) for two different groups of subjects (teens and adults).
So far, I've made a basic graph using xyplot(y ~x, group=subnum, data=mydata, type="b").
Now I would like to make all the teens' lines one color and the adults'
2005 Feb 03
1
If this is should be posted elsewhere, please advise
Hi,
I am puzzled by the relationship between the p-values asociated with the
coefficients of a univariate logistic regression involving categorical
variables and the p-value I get from Fisher's exact test of the
associated 2 x 2 contingency table.
(1) The 2-sided p-value for the table is ~ 0.0015, whereas the p-value
for the independent is 0.101 and the p-value for the intercept is