Questions tagged [car]

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

1) CAR refers to Conditional Auto-Regressive models, which are used in spatial statistics. A discussion of spatial models appears in the thread at http://stats.stackexchange.com/questions/277/spatial-statistics-models-car-vs-sar.

2) car is also an R package. The name stands for Companion to Applied Regression. It contains various datasets and visualisation functions useful for regression analysis. For a detailed description see the CAR documentation.

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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 doing the ANOVA using the car package but the output of…
cheedep
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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 confidence intervals and so on. The general idea being…
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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 leverage.plot() it says that "These functions display a generalization, due to Sall (1990), of added-variable plots…
Giorgos
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Difference between residual plots in plot(gam.object) and crplots(model)?

Both plot(gam.object)(regardless of whether in mgcv or gam) and car::crplots(model) plot the partial residuals of a predictor and the corresponding non-parametric smoother. True or False? If False, what then is the difference between both…
gammer
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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 coefficients and p-values for the relationship…
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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 have the main and interaction effects of them. Here…
qinli Deng
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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 networks, though less so. I also have an amateur…
Joe Hoover
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"aliased coefficients"

I tied to make make a "linearHypothesis" to test joint significance with the "car" package in R. However I got the error massage "there are aliased coefficients in the model." My regression runs over 6 periods and includes time-dummies, interaction…
Sonne
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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: > head(x) Type Bin Score 1 0 SI 2.120 2 0 R 2.246 3 0 R 2.246 4 0 R 2.511 5 0 R 2.420 6 0 R 2.270 > summary(x) Type Bin …
Madhura
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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 drinking. The class balance between a binge drinker and…
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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 the autocorrelation among the errors as…
Jack Shi
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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 that are factors). I was able to get p-values for…
stephanie
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ANCOVA when response variable is calculated from 2 covariates

I have an experiment in which I apply a treatment (g), and measure variables X and Y; the response variable (density; Z) is simply X/Y. If I wanted to know if X or Y, when shifted under the treatment, has a bigger influence on shifting Z under the…
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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 of the list would have contained m columns, with…
Ariel
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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 severity type. What does the result mean?
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