Displaying 20 results from an estimated 8000 matches similar to: "more on acf mis-feature (PR#1177)"
2001 Nov 19
2
acf mis-feature (PR#1177)
Full_Name: Hiroyuki Kawakatsu
Version: 1.3.1
OS: win2k
Submission from: (NULL) (130.158.140.105)
the lag labels in the acf plot is screwed when the ts frequency>1.
try, for example,
#acf mis-feature
x <- ts(rnorm(200), frequency=4);
acf(x,lag.max=24);
h.
> version
_
platform i386-pc-mingw32
arch x86
os Win32
system x86, Win32
2004 Aug 17
1
suggestion for ARMAacf()
hi,
in 1.9.1, the return value from ARMAacf(pacf=TRUE) is not named by lags,
contrary to ?ARMAacf. the simple fix is to move names(Acf) <-
down after if(pacf), with an appropriate starting lag as pacf=TRUE appears
to start at lag 1 (whereas pacf=FALSE starts at lag 0).
for consistency, one could argue to append 1 for lag 0 for pacf=TRUE
(or start pacf=F at lag 1). however, given the
2006 Aug 18
3
Query: how to modify the plot of acf
I need to modify the graph of the autocorrelation. I tried to do it through plot.acf but with no success.
1. I would like to get rid of the lag zero
2. I would like to have numbers on the x-axis only at lags 12, 24, 36, 48, 60, ...
Could anybody help me in this?
Any help will be appreciated
Thank you for your attention
Stefano
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2008 Nov 20
1
different ACF results
Dear all,
I have one Model (M3) fitted using the lme package, and I have
checked the correlation structure of within-group errors using
plot(ACF (M3,maxLag=10),alpha=0.05)
But now I am not sure how to interpret this plot for the empirical
autocorrelation function.
The problem is that I am used to see/interpret diagrams in which all
the autocorrelation Lags, except lag-1, are inside the
2010 Jul 06
1
acf
Hi list,
I have the following code to compute the acf of a time series
acfresid <- acf(residfit), where residfit is the series
when I type acfresid at the prompt the follwoing is displayed
Autocorrelations of series ?residfit?, by lag
0.0000 0.0833 0.1667 0.2500 0.3333 0.4167 0.5000 0.5833 0.6667 0.7500 0.8333
1.000 -0.015 0.010 0.099 0.048 -0.014 -0.039 -0.019 0.040 0.018
2008 May 08
2
acf function
Dear all,
I have an annual time-series of population numbers and I would like to
estimate the auto-correlation. Can I use acf() function and judge
whether auto-correlation is significant by the plots? The acf array, eg:
Autocorrelations of series 'x$log.s.r', by lag
0 1 2 3 4 5 6 7 8 9
10 11 12
1.000 0.031 -0.171
2006 Oct 28
1
labelling of horizontal axis in acf function
this one is not a false alarm like my previous message.
i have cut and paste the code below so if anyone could run it would be
appreciated. basically,
my question is why the horizontal axis of the acf plot is labelled with
such huge numbers when
the labels should be 1 through 10 since may lag.max = 10 ?
i looked at the cdoe of acf but it was pretty much beyond me. i think it
has something to
2009 Aug 05
2
acf Significance
Hi List,
I'm trying to calculate the autocorrelation coefficients for a time
series using acf at various lags. This is working well, and I can get
the coefficients without any trouble. However, I don't seem to be able
to obtain the significance of these coefficients from the returned acf
object, largely because I don't know where I might find them.
It's clear that the acf
2005 Oct 10
1
acf.plot() question
When I run the "acf()" function using the "acf(ts.union(mdeaths,
fdeaths))" example, the "acf()" function calls the "acf.plot()"
function to generate this plot...
http://members.cox.net/ddebarr/images/acf_example.png
The plot in the lower right-hand corner is labeled "fdeaths & mdeaths",
but the negative lags appear to belong to "mdeaths
2012 Dec 30
1
acf () and pacf()
I have used acf() and pacf() in R to get the acf and pacf values at
max/lag=20
but the output did not show the values associated with lag numbers. lag
numbers is shown in decimals.
--
Rashid Ameer
View my recent publication at
*
http://www.emeraldinsight.com/fwd.htm?id=aob&ini=aob&doi=10.1108/17538391211282854
*
Details for my works are available directly at
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
2000 Apr 04
0
stochastic process transition probabilities estimation
Hi all,
I'm new with R (and S), and relatively new to statistics (I'm a
computer scientist), so I ask sorry in advance if my question is silly.
My problem is this: I have a (sample of a) discrete time stochastic
process {X_t} and I want to estimate
Pr{ X_t | X_{t-l_1}, X_{t-l_2}, ..., X_{t-l_k} }
where l_1, l_2, ..., l_k are some fixed time lags. It will be enough for
me to compute
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 <-
2004 Jan 14
3
How can I test if time series residuals' are uncorrelated ?
Ok I made Jarque-Bera test to the residuals (merv.reg$residual)
library(tseries)
jarque.bera.test(merv.reg$residual)
X-squared = 1772.369, df = 2, p-value = < 2.2e-16
And I reject the null hypotesis (H0: merv.reg$residual are normally
distributed)
So I know that:
1 - merv.reg$residual aren't independently distributed (Box-Ljung test)
2 - merv.reg$residual aren't indentically
2012 Jul 28
4
quantreg Wald-Test
Dear all,
I know that my question is somewhat special but I tried several times to
solve the problems on my own but I am unfortunately not able to compute the
following test statistic using the quantreg package. Well, here we go, I
appreciate every little comment or help as I really do not know how to tell
R what I want it to do^^
My situation is as follows: I have a data set containing a
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:
2005 May 12
3
acf problem ?
Hi
I'm getting the following error that do not make sense to me, what am
Idoing wrong ?
> acf(Recsim[1,], lag.max=1)
Error in acf(Recsim[1, ], lag.max = 1) : 'lag.max' must be at least 1
Regards
EJ
2004 Jan 08
1
Help with acf
I would like to get the result of acf min of lag 2 and max of lag 50.
When I use time series ( acf, lag.max = 50, type="covariance"), I
got lag 0 to lag 50. How do I get lag 2 to lag 50?
Sincerely,
Stephen
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
2006 Oct 02
1
CCF and ACF
Dear all,
given two numeric vectors x and y, the ACF(x) at lag k is
cor(x(t),x(t+k)) while the CCF(x,y) at lag k is cor(x(t),y(t-k)). See
below for a simple example.
> set.seed(1)
> x <- rnorm(10)
> y <- rnorm(10)
> x
[1] -0.6264538 0.1836433 -0.8356286 1.5952808 0.3295078 -0.8204684
0.4874291 0.7383247 0.5757814 -0.3053884
> y
[1] 1.51178117 0.38984324