Displaying 20 results from an estimated 6000 matches similar to: "Why can't Anove (car package) see the data?"
2008 Jun 20
1
omnibus LR in multinomial model
If one estimates a model using multinom, is it possible to perform the
omnibus LR test ( the analogue to omnibus F in linear models ) using
the output
from multinom ? The residual deviance is there but I was hoping I could
somehow pull out the deviance based on just using an intercept ?
Sample code is below from the CAR book but I wasn't sure how to do it
based on that example. Thanks
2002 Apr 19
4
Durbin-Watson test in packages "car" and "lmtest"
Hi,
P-values in Durbin-Watson test obtained through the use of functions available in packages "lmtest" and "car" are different. The difference is quite significant. function "dwtest" in "lmtest" is much faster than "burbinwatson" in "car". Actually, you can take a nap while the latter trying to calculated Durbin-Watson test. My question
2010 Jan 03
1
Anova in 'car': "SSPE apparently deficient rank"
I have design with two repeated-measures factor, and no grouping
factor. I can analyze the dataset successfully in other software,
including my legacy DOS version BMDP, and R's 'aov' function. I would
like to use 'Anova' in 'car' in order to obtain the sphericity tests
and the H-F corrected p-values. I do not believe the data are truly
deficient in rank. I
2011 Jan 14
1
Question about scatterplot in package car
I am getting an error message from scatterplot:
> library(car)
> scatterplot(Prestige$income~Prestige$type)
Error in Summary.factor(c(2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, :
range not meaningful for factors
In addition: Warning message:
In Ops.factor(x[floor(d)], x[ceiling(d)]) : + not meaningful for factors
>
The command does output the kind of graph that I want (boxplots).
2008 Nov 19
2
GAMM and anove.lme question
Greetings all
The help file for GAMM in mgcv indicates that the log likelihood for a
GAMM reported using
summary(my.gamm$lme) (as an example) is not correct.
However, in a past R-help post (included below), there is some indication
that the likelihood ratio test in anova.lme(mygamm$lme, mygamm1$lme) is
valid.
How can I tell if anova.lme results are meaningful (are AIC, BIC, and
logLik
2008 Feb 06
1
box.Cox.powers() warning
Dear Rlist,
Using an example in box.cox.powers() help, I have the following warning message.
example:
library(car)
>attach(Prestige)
> box.cox.powers(income)
Box-Cox Transformation to Normality
Est.Power Std.Err. Wald(Power=0) Wald(Power=1)
0.1793 0.1108 1.6179 -7.4062
L.R. test, power = 0: 2.7103 df = 1 p = 0.0997
L.R. test, power = 1: 47.261 df = 1 p = 0
2009 Nov 08
2
linear trend line and a quadratic trend line.
Dear list users
How is it possible to visualise both a linear trend line and a quadratic trend line on a plot
of two variables?
Here my almost working exsample.
data(Duncan)
attach(Duncan)
plot(prestige ~ income)
abline(lm(prestige ~ income), col=2, lwd=2)
Now I would like to add yet another trend line, but this time a quadratic one. So I have two
trend lines. One linear trend line
2008 Jun 04
1
Comparing two regression lines
Dear R users,
Suppose I have two different response variables y1, y2 that I regress separately on the same
explanatory variable, x; sample sizes are n1=n2.
Is it legitimate to compare the regression slopes (equal variances assumed) by using
lm(y~x*FACTOR),
where FACTOR gets "y1" if y1 is the response, and "y2" if y2 is the response?
The problem I see here is that the
2012 Jul 28
4
quantreg Wald-Test
Dear all,
I know that my question is somewhat special but I tried several times to
solve the problems on my own but I am unfortunately not able to compute the
following test statistic using the quantreg package. Well, here we go, I
appreciate every little comment or help as I really do not know how to tell
R what I want it to do^^
My situation is as follows: I have a data set containing a
2008 Sep 02
1
multinomial estimation output stat question - not R question
I am estimating a multinomial model with two quantitative predictors, X1
and X2, and 3 responses. The responses are called neutral, positive and
negative with neutral being the baseline. There are actually many models
being estimated because I estimate the model over time and also for
various parameter sets but that's not important. When I estimate a
model, since neutral is the baseline
2005 Sep 05
2
model comparison and Wald-tests (e.g. in lmer)
Dear expeRts,
there is obviously a general trend to use model comparisons, LRT and AIC
instead of Wald-test-based significance, at least in the R community.
I personally like this approach. And, when using LME's, it seems to be
the preferred way (concluded from postings of Brian Ripley and Douglas
Bates' article in R-News 5(2005)1), esp. because of problems with the
d.f. approximation.
2009 May 05
2
Stepwise logistic Regression with significance testing - stepAIC
Hello R-Users,
I have one binary dependent variable and a set of independent variables (glm(formula,…,family=”binomial”) ) and I am using the function stepAIC (“MASS”) for choosing an optimal model. However I am not sure if stepAIC considers significance properties like Likelihood ratio test and Wald test (see example below).
> y <- rbinom(30,1,0.4)
> x1 <- rnorm(30)
> x2
2012 Sep 25
1
appropriate test in glm when the family is Gamma
Dear R users,
Which test is most appropriate in glm when the family is Gamma?
In the help page of anova.glm, I found the following
?For models with known dispersion (e.g., binomial and Poisson fits) the chi-squared test is most appropriate, and for those with dispersion estimated by moments (e.g., gaussian, quasibinomial and quasipoisson fits) the F test is most appropriate.?
My questions :
2013 Apr 24
1
Trouble Computing Type III SS in a Cox Regression using drop1 and Anova
Hello All,
Am having some trouble computing Type III SS in a Cox Regression using either drop1 or Anova from the car package. Am hoping that people will take a look to see if they can tell what's going on.
Here is my R code:
cox3grp <- subset(survData,
Treatment %in% c("DC", "DA", "DO"),
c("PTNO", "Treatment", "PFS_CENSORED",
2012 May 01
2
Hypothesis Testing using Wald Criterion for two regression models with dummy variables
I have two models, controlled by dummy variables to see if the models can be
combined into one model with similar intercepts and slopes. Has anyone tried
to conduct this type of test in R. I am utilizing the econometric idea of
hypothesis testing through the hypothesis of coincidence. I have tried to
run an anova with test of Chisq, but I am not sure what the results are
telling. In addition, I
2011 Sep 29
1
F and Wald chi-square tests in mixed-effects models
I have a doubt about the calculation of tests for fixed effects in
mixed-effects models.
I have read that, except in well-balanced designs, the F statistic that
is usually calculated for ANOVA tables may be far from being distributed
as an exact F distribution, and that's the reason why the anova method
on "mer" objects (calculated by lmer) do not calculate the denominator
df nor a
2007 Nov 09
1
White's test again
Hi all,
It seems that I can get White's (HC3) test using MASS. The syntax I
used for the particular problem is
anova(scireg3, white.adjust="hc3")
where scireg3 is an object from the lm function. But, the anova summary
table is all I get. I don't get the new estimates or standard errors
correcting for heteroskedasticity. Is there a way to get that information?
Thanks
2011 Nov 19
1
wald test: compare quantile regression estimators from different samples
Dear all,
I am trying to compare the estimated coefficients of a quantile regression model between two different samples. It is a Wald test, but I cannot find one way to do that in R.The samples are collected conditional on a specific characteristic and I would like to test whether such characteristic indeed affect the estimators. The problem in the test anova.rq is that the response variable
2002 Nov 02
1
problem with expand.model.frame
Dear R list members,
I'm encountering a problem with expand.model.frame(): Suppose that I define
the following simple function (meant
just to illustrate the problem):
> fun <- function(model){
+ expand.model.frame(model, all.vars(formula(model)))
+ }
>
and I have the following model, created with an explicit data argument:
> mod
Call:
2005 Aug 08
1
get the wald chi square in binary logistic regression
hello,
I work since a few time on R and i wanted to know how to obtain the Wald chi
square value when you make a binary logistic regression. In fact, i have the z
value and the signification but is there a script to see what is the value of
Wald chi square. You can see my model below,
Best regards,
S??verine Erhel
[Previously saved workspace restored]
> m3 = glm(reponse2 ~ form +