Displaying 20 results from an estimated 5000 matches similar to: "dw statistic"
2001 Nov 20
1
warning message
Hello everybody.
I would like to pose a question regarding a warning message after running
a function of my own. The function I created for computing the p-value of
the dw statistic has a command line like this:
»dwf0 <- function(dw,eigen) { carfun <- function(x) {
(prod(1+2*(eigen-dw)*1i*x)^(-1/2)-prod(1-2*(eigen-dw)*1i*x)^(-1/2))/(1i*x) }
; 1/2+integrate(f=carfun,lower = 0,upper =
2002 Apr 19
4
Durbin-Watson test in packages "car" and "lmtest"
Hi,
P-values in Durbin-Watson test obtained through the use of functions available in packages "lmtest" and "car" are different. The difference is quite significant. function "dwtest" in "lmtest" is much faster than "burbinwatson" in "car". Actually, you can take a nap while the latter trying to calculated Durbin-Watson test. My question
2009 Aug 03
1
Comparison of Output from "dwtest" and "durbin.watson"
Should "dwtest" and "durbin.watson" be giving me the same DW statistic and
p-value for these two fits?
library(lmtest)
library(car)
X <- c(4.8509E-1,8.2667E-2,6.4010E-2,5.1188E-2,3.4492E-2,2.1660E-2,
3.2242E-3,1.8285E-3)
Y <- c(2720,1150,1010,790,482,358,78,35)
W <- 1/Y^2
fit <- lm(Y ~ X - 1)
dwtest(fit,alternative="two.sided")
2007 Mar 07
2
where can I find Durbin-Waston test tables for Confidence Level 2.5% or 0.5%?
Hi all,
I am doing a two-sided DW test:
H0: rho = 0
H1: rho =/= 0
My understanding is that most test statistics tables are one-sided. It's the
way they created the table.
So from online, by doing Googling, I found a bunch of DW tables for
Confidence Level 5%.
Those tables can answer my two-sided question at 5x2 = 10% confidence level.
But what if I want two-sided test at 1% and 5%
2011 Aug 12
1
Which Durbin-Watson is correct? (weights involved) - using durbinWatsonTest and dwtest (packages car and lmtest)
Hello!
I have a data frame mysample (sorry for a long way of creating it
below - but I need it in this form, and it works). I regress Y onto X1
through X11 - first without weights, then with weights:
regtest1<-lm(Y~., data=mysample[-13]))
regtest2<-lm(Y~., data=mysample[-13]),weights=mysample$weight)
summary(regtest1)
summary(regtest2)
Then I calculate Durbin-Watson for both regressions
2005 May 19
1
Calculation of Durbin-Watson p-value
Sir,
I am unable to get the source code for Durbin-Watson test, as I want to calculate the p-value for Durbin Watson statistic using interpolation method. I sent this mail to r-help, but it was rejected, please suggest me some way. I will be highly greatful to you.
Thanks in advance
Ramesh
[[alternative HTML version deleted]]
2004 Jul 21
2
Testing autocorrelation & heteroskedasticity of residuals in ts
Hi,
I'm dealing with time series. I usually use stl() to
estimate trend, stagionality and residuals. I test for
normality of residuals using shapiro.test(), but I
can't test for autocorrelation and heteroskedasticity.
Is there a way to perform Durbin-Watson test and
Breusch-Pagan test (or other simalar tests) for time
series?
I find dwtest() and bptest() in the package lmtest,
but it
2009 Aug 05
2
Durbin-Watson
Hi,
I ran an experiment with 3 factors, 2 levels and 200 replications and as I want to test for residuals independence, I used Durbin-Watson in R.
I found two functions (durbin.watson and dwtest) and while both are giving the same rho, the p-values are greatly differ:
> durbin.watson(mod1)
lag Autocorrelation D-W Statistic p-value
1 -0.04431012 2.088610 0.012
Alternative
2003 Aug 13
1
means comparison with seasonal time series?
Dear R list,
I have a sequence of weekly observations of number of adults and larvae
in various size classes from a butterfly population living in a
subtropical area with pronounced wet and dry seasons. Wet and dry
seasons are each defined 26 weeks long with fixed start and end dates.
The data span 103 weeks (two seasons each of wet and dry) with some
missing weeks. What I would like to do is
2011 Nov 20
2
I'm writing this letter to enquire where can I download the package of "lmtest".
Dear editor:
I'm writing this letter to enquire where can I download the package of "lmtest". Can you send me this package?
THanks a lot.
Best regards,
Shu-Fei Wu
2011 Mar 16
1
Autocorrelation in linear models
I have been reading about autocorrelation in linear models over the last
couple of days, and I have to say the more I read, the more confused I
get. Beyond confusion lies enlightenment, so I'm tempted to ask R-Help for
guidance.
Most authors are mainly worried about autocorrelation in the residuals,
but some authors are also worried about autocorrelation within Y and
within X vectors
2004 Apr 16
2
regression and dw
Dear R People:
Suppose we have a regression model that we will call
y.lm
We run the Durbin Watson test for autocorrelation
and we find that there is positive autocorrelation,
and phi = 0.72, say.
What is our next step, please?
Do we calculate the following
yprime_t = y_t - 0.72y_t-1,
x1prime_t = x1_t - 0.72x1_t-1,
and so on, and re-fit the linear mode?
I haven't done this in a while.
2011 Jul 29
1
[LLVMdev] alignment checking in isSafeToEliminateVarargsCast
I have a question about a problem I came across while I was adding support
for aggregate va_arg expression in clang.
The following is the example program I will use in this email. I compile the
program with clang targeting mips. Note that I have not pushed all the
changes I have made yet, so you will not be able to see the same results.
$ clang -ccc-host-triple mipsel-unknown-linux
2017 Jun 06
1
Files Missing on Client Side; Still available on bricks
Hello,
I am still working at recovering from a few failed OS hard drives on my gluster storage and have been removing, and re-adding bricks quite a bit. I noticed yesterday night that some of the directories are not visible when I access them through the client, but are still on the brick. For example:
Client:
# ls /scratch/dw
Ethiopian_imputation HGDP Rolwaling Tibetan_Alignment
Brick:
#
2011 Jan 17
2
ping_pong using o2cb and cman
I was testing ocfs2 on a 2 node cluster set up.
ocfs2-tools version is 1.6.3
ocfs2 kernel version is 2.6.36
Using cman on 2 nodes
node02 dw # ping_pong -rwm /data/test.dat 3
data increment = 2
14 locks/sec
node01 dw # ping_pong -rw /data/test.dat 3
data increment = 2
10 locks/sec
node02 dw # ping_pong -r /data/test.dat 3
1980 locks/sec
Using cman on 1 node
node02 dw #
2013 Jun 18
1
eigen(symmetric=TRUE) for complex matrices
R-3.0.1 rev 62743, binary downloaded from CRAN just now; macosx 10.8.3
Hello,
eigen(symmetric=TRUE) behaves strangely when given complex matrices.
The following two lines define 'A', a 100x100 (real) symmetric matrix
which theoretical considerations [Bochner's theorem] show to be positive
definite:
jj <- matrix(0,100,100)
A <- exp(-0.1*(row(jj)-col(jj))^2)
A's being
2003 Jun 04
1
Error Using dwtest
Hello all-
I have two time series, Index1stdiff and Comps1stdiff. I regressed the
first on the second and R returned the summary stats I expected. Then I
looked at and plotted the residuals. I then wanted to assess
autocorrelation characteristics and tried to run a Durbin-Watson using:
library(lmtest)
dwtest(formula=Index1stdiff~Comps1stdiff,alternative=c("greater"))
I am
2008 Jan 04
1
GLMMs fitted with lmer (R) & glimmix (SAS)
I'm fitting generalized linear mixed models to using several fixed effects (main effects and a couple of interactions) and a grouping factor (site) to explain the variation in a dichotomous response variable (family=binomial). I wanted to compare the output I obtained using PROC GLIMMIX in SAS with that obtained using lmer in R (version 2.6.1 in Windows). When using lmer I'm specifying
2019 Aug 19
1
[PATCH v7 0/9] drm: cec: convert DRM drivers to the new notifier API
Hi Dariusz, Hans,
I can apply the dw-hdmi patches if necessary.
Neil
On 19/08/2019 11:38, Hans Verkuil wrote:
> Hi all,
>
> The patches in this series can be applied independently from each other.
>
> If you maintain one of these drivers and you want to merge it for v5.4
> yourself, then please do so and let me know. If you prefer I commit it
> to drm-misc, then please
2008 Jul 27
1
help with durbin.watson
Hi,
I have two time series, y and x. Diff(y) and Diff(x) both show no
autocorrelation. But durbin.watson(lm(Diff(y)~lag(Diff(x),k=-4)) gives a DW
value of zero. How come the residule is autocorrelated while Diff(y) and
Diff(x) are not? Does anyone know if in my case a DW of zero indicates
serial correlation, or is it telling me that the DW statistics is not the
appropriate statistics to use here?