similar to: Question about lme and AR(1)

Displaying 20 results from an estimated 5000 matches similar to: "Question about lme and AR(1)"

2008 Jan 25
1
Trouble setting up correlation structure in lme
Hi, I'm trying to set up AR(1) as a correlation structure in modeling some data (attached file data.txt in text format) with lme, but have trouble getting it to work. Incent, Correctness, and Oppor are 3 categorical variables, Beta is a response variable, and Time is an equally-spaced variable with 6 time points (treated as a categorical variable as well). Basically I want to model the
2008 Oct 13
0
correlation structure in gls or lme/lmer with several observations per day
Hi, To simplify, suppose I have 2 observations each day for three days. I would like to define the correlation structure of these 6 observations as follows: the correlation of 2 observations on the same day is, say, alpha, the correlation for 2 observations one day apart is rho and the correlation for 2 observations 2 days apart is rho^2. I.e. I would like to have an AR1 correlation + a
2007 May 24
1
lme with corAR1 errors - can't find AR coefficient in output
Dear List, I am using the output of a ML estimation on a random effects model with first-order autocorrelation to make a further conditional test. My model is much like this (which reproduces the method on the famous Grunfeld data, for the econometricians out there it is Table 5.2 in Baltagi): library(Ecdat) library(nlme) data(Grunfeld)
2014 Apr 13
1
[Bug 915] New: segfault in error case : expr_evaluate_payload not checking payload->payload.desc being null
https://bugzilla.netfilter.org/show_bug.cgi?id=915 Summary: segfault in error case : expr_evaluate_payload not checking payload->payload.desc being null Product: nftables Version: unspecified Platform: x86_64 OS/Version: All Status: NEW Severity: normal Priority: P5 Component: nft
2016 Oct 20
2
[Bug 1092] New: nft v0.6 segfault in must_print_eq_op at expression.c:520 during 'nft monitor trace' in netdev filter
https://bugzilla.netfilter.org/show_bug.cgi?id=1092 Bug ID: 1092 Summary: nft v0.6 segfault in must_print_eq_op at expression.c:520 during 'nft monitor trace' in netdev filter Product: nftables Version: unspecified Hardware: x86_64 OS: All Status: NEW
2012 Sep 06
0
lme( y ~ ns(x, df=splineDF)) error
I would like to fit regression models of the form y ~ ns(x, df=splineDF) where splineDF is passed as an argument to a wrapper function. This works fine if the regression function is lm(). But with lme(), I get two different errors, depending on how I handle splineDF inside the wrapper function. A workaround is to turn the lme() command, along with the appropriate value of splineDF, into a text
2012 Sep 26
0
lme(y ~ ns(x, df=splineDF)) error
I would like to fit regression models of the form y ~ ns(x, df=splineDF) where splineDF is passed as an argument to a wrapper function. This works fine if the regression function is lm(). But with lme(), I get two different errors, depending on how I handle splineDF inside the wrapper function. A workaround is to turn the lme() command, along with the appropriate value of splineDF, into a text
2005 Jun 28
1
How to extract the within group correlation structure matrix in "lme"
Dear R users, I fitted a repeated measure model without random effects by using lme. I will use the estimates from that model as an initial estimates to do multiple imputation for missing values of the response variable in the model. I am trying to extract the within group correlation matrix or covariance matrix. here is my code: f = lme(y ~x0+x1+trt+tim+x1:tim +tim:trt,random=~-1|subj,
2013 Jun 08
2
[Bug 827] New: limit: support is broken
https://bugzilla.netfilter.org/show_bug.cgi?id=827 Summary: limit: support is broken Product: nftables Version: unspecified Platform: x86_64 OS/Version: All Status: NEW Severity: blocker Priority: P5 Component: nft AssignedTo: pablo at netfilter.org ReportedBy: eric at regit.org
2003 Nov 27
1
Missing files in directory listings
Hi A customer of mine has a strange problem with samba 2.2.8a They have a number of directories with 600 - 800 files in each directory. When new files are added to the directories, and they do a directory listing on their PC's ( Win 2000 pro SP2 and SP3 ), the last 10 files are not shown. THis happens both when using "explorer" or doing a `dir` in an command prom window. The
2006 Oct 30
3
correlation structure in lme without random effect
I was hoping to fit along the lines of g<-gl(20,5) y<-runif(100) fit<-lme(fixed=y~g,correlation=corAR1(0,~1|g)) But I get the error "Incompatible formulas for groups in "random" and "correlation"" Any help would be greatly appreciated. Ben
2004 Nov 16
1
lme, two random effects, poisson distribution
Hello, I have a dataset concerning slugs. For each slug, the number of pumps per one time slot was counted. The number of pumps follows Bi(30, p) where p is very small, thus could be approximated by Poisson dist. (# of pumps is very often = 0) The slugs were observed during 12 time slots which are correlated in time as AR(1). The time slots are divided into two categories: Resting time
2004 Jan 21
0
intervals in lme() and ill-defined models
There has been some recent discussion on this list about the value of using intervals with lme() to check for whether a model is ill-defined. My question is, what else can drive very large confidence intervals for the variance components (or cause the error message "Error in intervals.lme(Object) : Cannot get confidence intervals on var-cov components: Non-positive definite approximate
2007 Apr 11
0
Error with corCompSymm and lme fit for repeated measures
Dear R Friends, I need help with an error associated with corCompSymm in an lme fit. I am using a mixed effects model to analyze a split-plot with repeated measures and would like to fit with the compound symmetry correlation structure. This problem doesn't occur when using corAR1 or any of the other structures. I would greatly appreciate help on how to solve this issue. Here's my
2006 Jul 13
1
Extracting Phi from gls/lme
I am trying to extract into a scalar the value of Phi from the printed output of gls or lme using corAR1 correlation. ie I want the estimate of the autocorrelation. I can't see how to do this and haven't seen it anywhere in str(model.lme). I can get all the other information - fixed and random effects etc. Is there an obvious way so that I can save the brick wall some damage? TIA
2011 Nov 18
1
[R-sig-ME] account for temporal correlation
[cc'ing back to r-help] On Fri, Nov 18, 2011 at 4:39 PM, matteo dossena <matteo.dossena at gmail.com> wrote: > Thanks a lot, > > just to make sure i got it right, > > if (using the real dataset) from the LogLikelihood ratio test model1 isn't "better" than model, > means that temporal auto correlation isn't seriously affecting the model? yes. (or
2012 Aug 31
3
fitting lognormal censored data
Hi , I am trying to get some estimator based on lognormal distribution when we have left,interval, and right censored data. Since, there is now avalible pakage in R can help me in this, I had to write my own code using Newton Raphson method which requires first and second derivative of log likelihood but my problem after runing the code is the estimators were too high. with this email ,I provide
2012 May 31
1
anova of lme objects (model1, model2) gives different results depending on order of models
Hello- I understand that it's convention, when comparing two models using the anova function anova(model1, model2), to put the more "complicated" (for want of a better word) model as the second model. However, I'm using lme in the nlme package and I've found that the order of the models actually gives opposite results. I'm not sure if this is supposed to be the case
2007 Oct 22
2
having problems with the lme function
Dear R-users: I have some problems working with lme function, and i would be glad if anyone could help me. this kind of analysis i was used to do with PROC MIXED from SAS, but i would like to move to R, for many reasons... So, the problem is: Imagine the I have 3 factors: fact_A, fact_B and fact_C: The latter I would assume that is random, and the rest of them are fixed. Analysing the
2007 Mar 17
1
Correlated random effects in lme
Hello, I am interested in estimating this type of random effects panel: y_it = x'_it * beta + u_it + e_it u_it = rho * u_it-1 + d_it rho belongs to (-1, 1) where: u and e are independently normally zero-mean distributed. d is also independently normally zero-mean distributed. So, I want random effects for group i to be correlated in t, following an AR(1) process. Any idea of how