similar to: lmer and handling heteroscedasticity

Displaying 20 results from an estimated 500 matches similar to: "lmer and handling heteroscedasticity"

2005 Dec 12
2
convergence error (lme) which depends on the version of nlme (?)
Dear list members, the following hlm was constructed: hlm <- groupedData(laut ~ design | grpzugeh, data = imp.not.I) the grouped data object is located at and can be downloaded: www.anicca-vijja.de/lg/hlm_example.Rdata The following works: library(nlme) summary( fitlme <- lme(hlm) ) with output: ... AIC BIC logLik 425.3768 465.6087 -197.6884 Random effects:
2006 Jan 11
3
how to obtain "par(ask=TRUE)" with trellis-plots
Dear alltogether, how can a delay like possible with par(ask=TRUE) be attained while using trellis-plots within a loop or something like that? the following draws each plot without waiting for a signal (mouse-klick), so par() does not work for that: library(nlme) for(i in 1:3) { fitlme <- lme(Orthodont) par(ask=TRUE) # does not work with trellis.... print(
2006 Feb 09
1
effect sizes in lme/ multi-level models
Dear alltogether, I am searching for a way to determine "effect size" in multi-level models by using lme(). Coming from Psychology, for ordinary OLS there are measures (for meta-analysis, etc.) like CohensD <- (mean_EG - mean_CG) / SD_pooled or (p)eta^2 <- SS_effect / (SS_effect + SS_error) I do not intend to lead a discussion of the usefulness of such measures as long as
2005 Dec 06
3
strange behavior of loess() & predict()
Dear altogether, I tried local regression with the following data. These data are a part of a bigger dataset for which loess is no problem. However, the plot shows extreme values and by looking into the fits, it reveals very extreme values (up to 20000 !) although the original data are > summary(cbind(x,y)) x y Min. :1.800 Min. :2.000 1st Qu.:2.550
2006 Jan 09
2
decide between polynomial vs ordered factor model (lme)
Dear alltogether, two lme's, the data are available at: http://www.anicca-vijja.de/lg/hlm3_nachw.Rdata explanations of the data: nachw = post hox knowledge tests over 6 measure time points (= equally spaced) zeitn = time points (n = 6) subgr = small learning groups (n = 28) gru = 4 different groups = treatment factor levels: time (=zeitn) (n=6) within subject (n=4) within smallgroups
2005 Nov 09
2
error in NORM lib
Dear alltogether, I experience very strange behavior of imputation of NA's with the NORM library. I use R 2.2.0, win32. The code is below and the same dataset was also tried with MICE and aregImpute() from HMISC _without_ any problem. The problem is as follows: (1) using the whole dataset results in very strange imputations - values far beyond the maximum of the respective column, >
2005 Oct 29
1
how to get colnames of a dataframe within a function called by 'apply'
Hello alltogether, how is it possible to assign the colnames of a data.frame to a function called by apply, e.g. for labeling a plot? Example: I want to plot several qqnorm-plots side by side and there should be a maintitle for each qqnorm-plot which is identical to the respective colname. I checked, but the column which is processed by the function called by apply does not contain a colname
2008 Dec 26
1
starting values update
Hi all, does anyone know how to automatically update starting values in R? I' m fitting multiple nonlinear models and would like to know how I can update starting values without having to type them in. thank all --- On Fri, 12/26/08, r-help-request@r-project.org <r-help-request@r-project.org> wrote: From: r-help-request@r-project.org <r-help-request@r-project.org> Subject:
2006 Aug 07
1
mathematica -> r (gamma function + integration)
Dear R-list, I try to transform a mathematica script to R. #######relevant part of the Mathematica script (* p_sv *) dd = NN (DsD - DD^2); lownum = NN (L-DD)^2; upnum = NN (H-DD)^2; low = lownum/(2s^2); up = upnum/(2s^2); psv = NIntegrate[1/(s^NN) Exp[-dd/(2s^2)] (Gamma[1/2,0,up] + Gamma[1/2,0,low]),{s,sL,sH}, MinRecursion->3]; PSV = psv/Sqrt[2NN]; Print["------------- Results
2012 Sep 12
2
how to generate third table in test database
hi all, has_and_belongs_to_many :cows has_and_belongs_to_many :milkmans i am using has_and_belongs_to_many in my app.I know this will create third table internally cows_milkmans in mysql database. when i migrate develpoment database i have table cows_milkmans. Good no Problem till now. Now a problem start When i migrate test database there is no such cows_milkmans table is present..
2017 Aug 16
0
{nlme} Question about modeling Level two heteroscedasticity in HLM
If you don't get a response it is because you did not read the Posting Guide which indicates that the R-sig-ME mailing list is where this question would have been on-topic. -- Sent from my phone. Please excuse my brevity. On August 16, 2017 6:17:03 AM PDT, b88207001 at ntu.edu.tw wrote: >Hello dear uesRs, > >I am working on modeling both level one and level two
2017 Aug 16
0
{nlme} Question about modeling Level two heteroscedasticity in HLM
A better place for this post would be on R's mixed models list: r-sig-mixed-models . Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Wed, Aug 16, 2017 at 6:17 AM, <b88207001 at ntu.edu.tw> wrote: > Hello dear
2006 Aug 31
0
Moving Window regressions with corrections for Heteroscedasticity and Autocorrelations(HAC)
# Using Moving/Rolling Windows, here we do an OLS Regression with corrections for #Heteroscedasticity and Autocorrelations (HAC) using Newey West Method. This code is a #extension of Ajay Shah?s code for moving windows simple OLS regression. # The easiest way to adjust for Autocorrelations and Heteroscedasticity in the OLS residuals is to #use the coeftest function that is included in the
2016 Apr 15
1
Heteroscedasticity in a percent-cover dataset
Hi, I am currently trying to do a GLMM on a dataset with percent cover of seagrass (dep. var) and a suite of explanatory variables including algal (AC) and epiphyte cover (EC), rainfall, temperature and sunshine hours. M2=glmer(SG~AC+EC+TP+SS+RF+(1|Location/fSi/fTr), family=binomial,data=data,nAGQ=1) As the dependent variable is percent cover, I used a binomial error structure. I also have a
2008 Sep 04
2
Correct for heteroscedasticity using car package
Dear all, Sorry if this is too obvious. I am trying to fit my multiple regression model using lm() Before starting model simplification using step() I checked whether the model presented heteroscedasticity with ncv.test() from the CAR package. It presents it. I want to correct for it, I used hccm() from the CAR package as well and got the Heteroscedasticity-Corrected Covariance Matrix. I am not
2013 Feb 06
1
Heteroscedasticity Plots
To detect heteroscedasticity for a multiple linear OLS regression (no time dependencies): What if the residuals vs. fitted values plot shows well behaved residuals (cloud) - but the some of the x versus residuals plots are a megaphone? Also, it seems that textbooks and internet tutorials in R do not agree what is the best plot for detecting heteroscedasticity. What do you use? I found so
2006 Jul 26
2
Codes; White's heteroscedasticity test and GARCH models
Hello, I have just recently started using R and was wondering whether anybody had a code written for White's heteroscedasticity correction for standard errors. Also, can anybody share a code for the GARCH(1,1) and GARCH-in-mean models for modelling regression residuals? Thanks a lot in advance, Spyros --------------------------------- [[alternative HTML version
2008 Jul 22
1
How to simulate heteroscedasticity (correlation)
Hi, I would like to generate two correlated variables. I found that funktion for doing that: a <- rmvnorm(n=10000,mean=c(20,20),sigma=matrix(c(5,0.8*sqrt(50), 0.8*sqrt(50),10),2,2)) (using library(mvtnorm)) Now I also want to generate two correlated variables where the error variance vary over the variable-correlation. And I want to plot this for showing heteroscedasticity. Like shown
2012 Oct 07
1
Testing volatility cluster (heteroscedasticity) in stock return?
Dear All, i want to use garch model in return of stock. and the data should presence volatility cluster (Heteroscedasticity). Do you know how to test volatility cluster (the presence of heteroscedasticity) in series data of stock return in R? Is it using Langrange Multiplier (LM) ARCH test? what package i should use? I really need the help. Thanks for the attention. Eko A P
2013 Apr 18
1
Statistical test for heteroscedasticity for an object of class "gls"
Hi there, Does anyone know of a statistical test for heteroscedasticity for an object of class "gls"? (or alternative objective methods). Thanks in advance, Ben Gillespie, Research Postgraduate o-------------------------------------------------------------------o School of Geography, University of Leeds, Leeds, LS2 9JT o-------------------------------o http://www.geog.leeds.ac.uk/