Displaying 20 results from an estimated 30000 matches similar to: "variance inflation factor for linear mixed effects"
2012 Jun 28
1
SVY: variance inflation factor VIF with complex survey
Hello,
Seeking a way to get the variance inflation factor VIF for a model of regression in complex survey, I have understood that without this package (SURVEY) RGui VIF obtained as follows:
fit <- lm(mpg~disp+hp+wt+drat, data=mtcars)
vif(fit)
But I want to know if survey, Vif is obtained so
vif( svyglm(api00~ell+meals+mobility, design=dstrat))
Thank you, happy day
2012 Jul 11
1
Variance Inflation factor
Hi All,
I need to calculate VIF (variance inflation factor) for my linear regression model. I found there was a function named vif in 'HH' package. I have two questions:
1) I was able to install that package in my R under windows. But while trying to install that package in UNIX, I got error:
Package HH is not available.
Does somebody know why?
2) Does
2009 Mar 06
0
Variance inflation factors (VIF)
I have the following script, how can I implement to achieve that calculate
the VIF.
Thanks.
U1.7km<-c(15:24)
R<-c(1.2,0.2,3.6,2.5,4.8,6.3,2.3,4.1,7.2,6.1)
Hm<-c(1:10)
mod<-nls(R~a*(U1.7km^b)*(Hm^c), start=list(a=2.031, b=0.800, c=-0.255),
trace=T)
summary(mod)
coef(mod)
coef(summary(mod))
--
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2012 Sep 20
2
Variance Inflation Factor VIC() with a matrix
Hi everyone,
Running the vif() function from the car package like
----------------------------------------------------
> reg2 <- lm(CARsPur~Delay_max10+LawChange+MarketTrend_20d+MultiTrade,
data=data.frame(VarVecPur))
> vif(reg2)
Delay_max10 LawChange MarketTrend_20d MultiTrade
1.010572 1.009874 1.004278 1.003351
2003 Jul 23
6
Condition indexes and variance inflation factors
Has anyone programmed condition indexes in R?
I know that there is a function for variance inflation factors
available in the car package; however, Belsley (1991) Conditioning
Diagnostics (Wiley) notes that there are several weaknesses of VIFs:
e.g. 1) High VIFs are sufficient but not necessary conditions for
collinearity 2) VIFs don't diagnose the number of collinearities and 3)
No one has
2012 Mar 23
0
Fixing error variance in a path analysis to model measurement error in scales using sem package
Hi!
I want to construct a path analysis model that can account for measurement
error in totally aggregated parcels, which refer to parcels where all of
the items in a scale are summed or averaged. If I am not mistaken, Bollen
(1989) advocates the following formula for computing the error variance of
each parcel:
(1−α(parcel))×variance(parcel),
such that α refers to Cronbach's alpha, which
2008 Oct 29
0
reporting interactions of factors in linear mixed effects models
Hi,
I have a question about how I should report the results for a linear
mixed effects model where the model includes as predictors three
factors (facA, facB and facC), one of which (facA) interacts with the
other two. facA and facB have two levels and facC has 3 levels. There
are also several other continuous predictors (e.g. varA, varB, varC).
My mixed model is specified with the following
2008 Jan 31
0
How to calculate Intraclass-coefficient in 2-level Linear Mixed-Effects models?
Dear R-users,
consider a 2-level linear mixed effects model (LME) with random intercept
AND random slope for level 1 AND 2. Does anybody know how to calculate
Intraclass-coefficient (ICC) for highest (innermost) level 2 ??? In the
literature, I did not find an example for these kind of komplex models.
For 1-level Random-Intercept models it would be easy:
ICC = variance due to the clustering
2008 Apr 21
1
Regression inclusion of variable, effect on coefficients
Hello dear R users!
I know this question is not strictly R-help, yet, maybe some of the guru's
in statistics can help me out.
I have a sample of data all from the same "population". Say my regression
equation is now this:
m1 <- lm(y ~ x1 + x2 + x3)
I also regress on
m2 <- lm(y ~ x1 + x2 + x3 + x4)
The thing is, that I want to study the effect of
2003 Feb 26
0
(no subject)
Let's assume that the columns of the model matrix, apart perhaps
from an initial column that corresponds to the overall mean, have
been centred. Then:
1) Normal equation methods give an accurate fit to the matrix
of centred sums of squares and products.
2) QR methods give an accurate fit to the predicted values.
QR will give better precision than normal equation methods
(e.g., Cholesky) if
2007 Jun 28
1
unequal variance assumption for lme (mixed effect model)
Dear Douglas and R-help,
Does lme assume normal distribution AND equal variance among groups
like anova() does? If it does, is there any method like unequal
variance T-test (Welch T) in lme when each group has unequal variance
in my data?
Thanks,
Shirley
2009 Jul 10
1
Degree of freedom in the linear mixed effect model using lme function in R
Hello,
I would appreciate if somebody could help me clear my mind about the below issues.
I have a factorial experiment to study the effects of Grazing and Fire on Forest biomass production. The experimental unit (to which the treatment combinations are applied) are PLOTs. The measures were made repeatedly for 13 years.
I am planning to use the linear mixed effect model function lme in R for this.
2017 Oct 31
0
Course in Lisbon: Introduction to Linear Mixed Effects Models and GLMM with R
We would like to announce the following statistics course:
Course: Introduction to Linear Mixed Effects Models and GLMM with R
Where:? Lisbon, Portugal
When:?? 19-23 February 2018
Course website: http://highstat.com/index.php/courses
Course flyer:
http://highstat.com/Courses/Flyers/2018/Flyer2018_02LisbonV2.pdf
Kind regards,
Alain Zuur
--
Dr. Alain F. Zuur
Highland Statistics Ltd.
9 St
2008 Aug 25
1
A repeated measures, linear mixed model (lme) WITHOUT random effects...
Hello,
I am trying to fit a repeated measures linear mixed model (using lme)
but I don't want to include any random effects. I'm having trouble (even
after consulting Pinheiro & Bates 2000) figuring out how to specify the
repeated measure without including it in the specification of a random
effect.
My data consist of repeated "counts" in "plots" that I wish
2007 Oct 22
2
Repeated Measures/Linear Mixed Effects function
I have three columns of data, Xc, Trt and fish. This was a repeated
measures design with 6 measurements taken from each of 5 fish. Xc is the
actual measurement, Trt is the treatment, and fish is the fish number. Data
can be seen below (hopefully it is in the column format). I would like to
look for differences between treatments in a repeated measures format. I
used the following code
2007 Jul 08
0
random effect variance per treatment group in lmer
All,
How does one specify a model in lmer such that say the random effect for
the intercept has a different variance per treatment group?
Thus, in the model equation, we'd have say b_ij represent the random
effect
for patient j in treatment group i, with variance depending on i, i.e,
var(b_ij) = tau_i.
Didn't see this in the docs or Pinherio & Bates (section 5.2 is specific
for
2006 Oct 16
1
linear mixed effects models with breakpoints
Hi folks
I have some data to which I've been fitting linear mixed effects
models. I am currently using a lme model in the nlme package, with terms
for random effects due to repeated measures on individuals and the
corCAR1 serial correlation structure. However, there is some suggestion
in the data (and from theory) that a breakpoint (change point) model may
be more appropriate. Scott, Norman
2013 Nov 21
0
Course: Introduction to Linear mixed effects models, GLMM and MCMC with R
We would like to announce the following statistics course;
Course: Introduction to Linear mixed effects models, GLMM and MCMC with R
When: 10-14 February, 2014
Where: Pousada de juventude parque das nacoes. Rua de Moscavide, Lt 47 ?
101, 1998- 011. Lisbon, Portugal
Info: http://www.highstat.com/statscourse.htm
Flyer: http://www.highstat.com/Courses/Flyer2014_02SIM_LisbonV2.pdf
Kind regards,
2007 Feb 20
1
Simplification of Generalised Linear mixed effects models using glmmPQL
Dear R users I have built several glmm models using glmmPQL in the
following structure:
m1<-glmmPQL(dev~env*har*treat+dens, random = ~1|pop/rep, family =
Gamma)
(full script below, data attached)
I have tried all the methods I can find to obtain some sort of model fit
score or to compare between models using following the deletion of terms
(i.e. AIC, logLik, anova.lme(m1,m2)), but I
2002 Apr 12
1
summary: Generalized linear mixed model software
Thanks to those who responded to my inquiry about generalized linear
mixed models on R and S-plus. Before I summarize the software, I note
that there are several ways of doing statistical inference for
generalized linear mixed models:
(1)Standard maximum likelihood estimation, computationally intensive
due to intractable likelihood function
(2) Penalized quasi likelihood or similar