Questions tagged [car]

CAR refers to the Conditional Auto-regressive models, which is used in spatial statistics.

Filter by
Sorted by
Tagged with
0
votes
0answers
5 views

Conditional Autoregressive (CAR) model in a non-Bayesian framework?

The Conditional Auto-regressive (CAR) model is used to capture spatial variation in a dataset. Most of the works I have seen considering CAR model is in Bayesian framework. My question is can the CAR ...
0
votes
0answers
10 views

Posterior Predictive CARBayesST

I'm trying to use the CARBayesST package and I need to do Spatio-temporal predictions. In the vignette of the package on page 27 says " If there had been saying m missing values, then the Y component ...
0
votes
0answers
17 views

Multivariate Bayesian Car Model Result

I have developed a multivariate Bayesian Car model for three crash severity level analysis. I found that the covariance for both heterogenous effects and the spatial effect is not significant for any ...
0
votes
0answers
20 views

Wrong sign of a model coefficient in Bayesian Poisson-Lognormal Car model

I am trying to develop a multivariate Poisson lognormal CAR model. One of my most important variables in the model is providing a negative sign which should be positive. However, when I develop a ...
0
votes
0answers
42 views

Winbugs code multivariate hierarchical Poisson Log-normal CAR model

I am looking for some example code to develop multivariate hierarchical Poisson Log-normal CAR model using Winbugs. Can anyone help me with similar reserach that added their code? Also, how can I ...
0
votes
0answers
77 views

Out-of-sample prediction in conditional autoregressive models

I am interested in fitting a conditional autoregressive model to a dataset where observations are grouped by regions, then performing cross-validation by holding out all observations from a single ...
3
votes
1answer
114 views

why does ignoring spatial autocorrelation lead to spurious significance

In spatial statistics one often hears the statements like the following: unaccounted for spatial autocorrelation may lead to spurious significance / understimated uncertainty / too narrow ...
1
vote
0answers
1k views

Understanding the Anova (car package) output in r

I am running a two-way anova test using Anova from car package. My data looks like this: ...
0
votes
0answers
102 views

Strength Parameter in ICAR Spatial Model

As I understand it, the parameter $\alpha \in [0, 1]$ that controls strength of spatial association in a CAR model gets set to 1 in an Intrinsic CAR model. Does this mean that an ICAR model cannot/...
2
votes
1answer
578 views

Difference between residual plots in plot(gam.object) and crplots(model)?

Both plot(gam.object)(regardless of whether in mgcv or gam) and ...
1
vote
2answers
451 views

Probing effects in a multivariate multiple regression

I'm trying to run a multivariate multiple regression in R, i.e. including multiple predictors and multiple outcome variables in the same linear regression model. Does anybody know how to pull out the ...
1
vote
1answer
753 views

Presenting results from tree classification methods

I am writing my thesis about binge drinking at my universitity. I have done a survey and collected 957 instances with 29 variables that could be interesting. I also got a binary value for binge ...
1
vote
0answers
140 views

whether the car::Anova function can be used for GLMM

Now, I am running a generalized linear mixed model using lme4 package. I have three category factors (factor 1 has three levels, factor 2 has two levels, factor 3 has five levels). And I want to ...
2
votes
0answers
361 views

Implementing a hierarchical bayesian model with latent independent and dependent variables for spatial analysis (in stan)

I am moderately familiar with frequentist hierarchical modeling, structural equation modeling, and hierarchical structural equation modeling. I am also moderately familiar with bayesian graphical ...
3
votes
0answers
282 views

leverage.plot() R - CAR package

I'm trying to complete a homework regarding added-variables and leverage plots using the CAR package. In the documentation of the ...
4
votes
0answers
1k views

Will Tukey multiple comparison be the same for different types of Sum Of Squares of ANOVA for an unbalanced design

I am working on Two-Way ANOVA for an unbalanced design. Will Tukey multiple comparison be the same for different types (I, II & III) of Sum Of Squares of ANOVA for an unbalanced design. I am ...
1
vote
0answers
406 views

Model checking for Spatial CAR (Conditional Autoregressive) model

We assume our data follow the model: $$ Y = X\beta +\varepsilon $$ In spatial CAR (SAR) model, we assume that the errors $\varepsilon$ are correlated in a spatial setting. Let's say that we model ...
1
vote
0answers
594 views

Different p-values between Wald Z and Wald Chisquare

I have used lme4 for mixed effects models of reaction times and accuracy rates. I could not use lmerTest because the type of model I was using are not yet implemented there (problem with predictors ...