Displaying 20 results from an estimated 5000 matches similar to: "delta AIC for models with 2 variables using MuMIn"
2010 Aug 17
2
AIC in MuMIn
Hello,
I am using package MuMIn to calculate AIC for a full model with 10
explanatory variables.
Thanks in advance in sharing your experience.
Q1
In the AIC list of all models, each model is differentiated by model number.
Please kindly advise if it is possible to
find the corresponding explanatory variable(s) for the model number.
Q2 error message
I tried to display sub-model with only
2011 Jul 13
3
Sum weights of independent variables across models (AIC)
Hello,
I'd like to sum the weights of each independent variable across linear
models that have been evaluated using AIC.
For example:
> library(MuMIn)
> data(Cement)
> lm1 <- lm(y ~ ., data = Cement)
> dd <- dredge(lm1, beta = TRUE, eval = TRUE, rank = "AICc")
> get.models(dd, subset = delta <4)
There are 5 models with a Delta AIC Score of
2010 Aug 17
2
how to selection model by BIC
Hi All:
the package "MuMIn" can be used to select the model based on AIC or AICc.
The code is as follows:
data(Cement)
lm1 <- lm(y ~ ., data = Cement)
dd <- dredge(lm1,rank="AIC")
print(dd)
If I want to select the model by BIC, what code do I need to use? And when
to select the best model based on AIC, what the differences between the
function "dredge" in
2012 Jan 17
1
MuMIn package, problem using model selection table from manually created list of models
The subject says it all really.
Question 1.
Here is some code created to illustrate my problem, can anyone spot where I'm going wrong?
Question 2.
The reason I'm following a manual specification of models relates to the fact that in reality I am using mgcv::gam, and I'm not aware that dredge is able to separate individual smooth terms out of say s(a,b). Hence an additional request,
2010 Aug 10
2
question about bayesian model selection for quantile regression
Hi All:
Recently I am researching my dissertation about the quantile model selection
by bayesian approach. I have the dependent variable(return) and 16
independent variables and I need to select the best variable for each
quantile of return. And the method I used is the bayesian approach, which is
based on calculating the posterior distibution of model identifier. In other
words, I need to obtain
2013 Jan 18
1
Object created within a function disappears after the function is run
Dear R-helpers,
I have run the code below which I expected to make an object called dd1,
but that object does not exist.
So, in summary, my problem is that my function is meant to make an object
(dd1), and it does indeed make that object (I know that the last line of
the function prints it out) but then, after the function has run, the
object has disappeared.
It's late on a Friday so I may
2013 Nov 07
2
Error running MuMIn dredge function using glmer models
Dear list,
I am trying to use MuMIn to compare all possible mixed models using the dredge function on binomial data but I am getting an error message that I cannot decode. This error only occurs when I use glmer. When I use an lmer analysis on a different response variable every works great.
Example using a simplified glmer model
global model:
mod<- glmer(cbind(st$X2.REP.LIVE,
2011 Oct 25
1
difficulties with MuMIn model generation with coxph
Hi All,
I'm having trouble with the automatized model generation (dredge) function
in the MuMIn package. I'm trying to use it to automatically generate subsets
of models from a global cox proportional hazards model, and rank them based
on AICc. These seems like it's possible, and the Mumin documentation says
that coxph is supported. However, when I run the code (see below), it gives
2013 Mar 29
2
Error message in dredge function (MuMIn package) used with binary GLM
Hi all,
I'm having trouble with the model generating 'dredge' function in the MuMIn
'Multi-model Inference' package.
Here's the script:
globalmodel<- glm(TB~lat+protocol+tested+
streams+goats+hay+cattle+deer,
family="binomial")
chat<- deviance(globalmodel)/59 #There we 59 residual degrees of freedom in
this global model.
models<- dredge(globalmodel,
2024 Jul 31
1
Difference between stats.steps() and MuMIn.dredge() to select best fit model
Hello,
I try to understand the different approaches how to select the best fit
regression model.
This is not about AIC, BIC, etc. It is about the difference between the
steps() function
(in stats package) and the dredge() function (in MuMIn) package.
I see several examples on the internet.
step() explore the model space with a step wise approach.
And dredge() try out all possible combinations
2011 Feb 04
1
GAM quasipoisson in MuMIn
Hi,
I have a GAM quasipoisson that I'd like to run through MuMIn package
- dredge
- gettop.models
- model.avg
However, I'm having no luck with script from an example in MuMIn help file.
In MuMIn help they advise "include only models with smooth OR linear term
(but not both) for each variable". Their example is:
# Example with gam models (based on
2012 Jul 11
1
Package MuMIn (dredge): Error in ret[, ] <- cbind(x, se, rep(if (is.null(df)) NA_real_ else df, : number of items to replace is not a multiple of replacement length.
Hello R community,
I am attempting to run multiple logistic regressions (multinomial, via
package 'nnet'), with Automated Model Selection (dredge, package 'MuMIn').
The aim is to reduce the number of predictor variables by assessing relative
performance of each variable, which can be done in a coarse fashion using
the Automated Model Selection option in package 'MuMIn'
2012 Mar 23
3
Using MuMIn - error message
Hello,
I hope that you can bare with me. I am new to models, but I think I have a
pretty godd understanding of how to run them now, including how to use AICc
and Anova. The issue is that I have many factors that I wish to compare so
doing each one at a time would take forever.
I came across the MuMIn package and I was so excited, however I am getting
an error message and i don't know why.
2012 Jun 24
1
MuMIn for GLM Negative Binomial Model
Hello
I am not able to use the MuMIn package (version 1.7.7) for multimodel inference with a GLM Negative Binomial model (It does work when I use GLM Poisson). The GLM Negative Binomial gives the following error statement:
Error in get.models(NBModel, subset = delta < 4) :
object has no 'calls' attribute
Here is the unsuccessful Negative Binomial code.
>
> BirdNegBin
2011 Aug 29
1
MuMIn Problem getting adjusted Confidence intervals
Hello R users
I'm using MuMIn but for some reason I'm not getting the adjusted confidence
interval and uncoditional SE whe I use model.avg().
I took into consideration the steps provided by Grueber et al (2011)
Multimodel inference in ecology and evolution: challenges and solutions in
JEB.
I created a global model to see if malaria prevalence (binomial
distribution) is related to any
2010 Aug 15
1
how to display delta AIC of all models
Dear all,
I am making model selection of generalised linear models based on delta
AIC,
using the command step(AIC).
Also, I would like to learn the explanatory powers of each independent
variable.
To phrase differently, it is in need to show the delta AIC of all models
rather than the final model with the least delta AIC.
Please kindly advise if it is possible to exhibit all delta AIC of
2013 Apr 01
0
Error message in dredge function (MuMIn package) with binary GLM
Hi all,
My replies within the forum aren't getting approved, though my emails
always go through, so here is my reply to a question I previously
posted (all questions and answers shown). Thanks, Cat
I'm having trouble with the model generating 'dredge' function in the MuMIn
'Multi-model Inference' package.
Here's the script:
globalmodel<-
2012 Jul 27
0
dredge solely offset models in MuMIn
hello everyone,
I'm modelling in lmer an average chick weight defined as
"Total.brood.mass ~ offset(chick.number), with three fixed and two
random effect. Next, I want to use function dredge from MuMIn package
for model averaging. Not sure why, but in consequence the offset
variable is treated as a predictor, so I get a table that mixes models
with and without that offset term (the first
2012 Jun 26
2
MuMIn - assessing variable importance following model averaging, z-stats/p-values or CI?
Dear R users,
Recent changes to the MuMIn package now means that the model averaging command (model.avg) no longer returns confidence intervals, but instead returns zvalues and corresponding pvalues for fixed effects included in models.
Previously I have used this package for model selection/averaging following Greuber et al (2011) where it suggests that one should use confidence intervals from
2012 Feb 13
2
R's AIC values differ from published values
Using the Cement hardening data in Anderson (2008) Model Based Inference in
the Life Sciences. A Primer on Evidence, and working with the best model
which is
lm ( y ~ x1 + x2, data = cement )
the AIC value from R is
model <- lm ( formula = y ~ x1 + x2 , data =
cement )
AIC ( model )
64.312
which can be converted to AICc by adding the bias