Displaying 20 results from an estimated 5000 matches similar to: "Small p-value good or bad?"
2010 Dec 10
1
survreg vs. aftreg (eha) - the relationship between fitted coefficients?
Dear R-users,
I need to use the aftreg function in package 'eha' to estimate failure times for left truncated survival data. Apparently, survreg still cannot fit such models. Both functions should be fitting the accelerated failure time (Weibull) model. However, as G?ran Brostr?m points out in the help file for aftreg, the parameterisation is different giving rise to different
2010 Nov 25
2
aftreg vs survreg loglogistic aft model (different intercept term)
Hi, I'm estimating a loglogistic aft (accelerated failure time) model, just a
simple plain vanilla one (without time dependent covariates), I'm comparing
the results that I obtain between aftreg (eha package) and survreg(surv
package). If I don't use any covariate the results are identical , if I add
covariates all the coefficients are the same until a precision of 10^4 or
10^-5 except
2011 May 02
3
ID parameter in model
Hello,
I am apparently confused about the use of an id parameter for an event
history/survival model, and why the EHA documentation for aftreg does
not specify one. All assistance and insights are appreciated.
Attempting to specifiy an id variable with the documentation example
generates an "overlapping intervals" error, so I sorted the original
mort dataframe and set subsequent entry
2011 May 21
1
predict 'expected' with eha package
I am unsure what is being returned, and what is supposed to be
returned, when using 'predict' with "type='expected'" for an aftreg
survival model. The code below first generates a weibull model, then
uses predict to create a vector of the linear predictors, then
attempts to create the 'expected' vector, which is empty. The final
two steps in the code generate a
2011 Nov 16
1
"Non-finite finite-difference value" error in eha's aftreg
Hi list!
I'm getting an error message when trying to fit an accelerated failure
time parametric model using the aftreg() function from package eha:
> Error in optim(beta, Fmin, method = "BFGS", control = list(trace =
> as.integer(printlevel)), :
> non-finite finite-difference value [2]
This only happens when adding four specific covariates at the same time
in the
2010 Feb 05
3
AFTREG with ID argument
Dear all,
I have some trouble using the "id"-argument with aftreg (accelerated
failure time regression analysis from the eha library).
As far as I understand it, the id argument is used to group
individuals together if there are time-varying covariates and the
data is arranged in counting process style.
Unfortunately, i cannot figure out how to use the "id"-argument. The
2008 Oct 22
2
Weibull parameter estimation
Dear R-users
I would like to fit weibull parameters using "Method of moments" in order to
provide the inital values of the parameter to de function 'fitdistr' . I
don`t have much experience with maths and I don't know how to do it.
Can anyone please put me in the rigth direction?
Borja
[[alternative HTML version deleted]]
2010 Feb 19
1
eha aftreg performance
G?ran, thanks for the update, I'm just about to install it!
Just wanted to drop you a short line about performance (as you once
requested):
aftreg takes ages on my windows machine to calculate a small set of
7 observations which are not even grouped together by "id". To be a
bit more precise, it takes 2:40 mins on my Intel T9300 Core2 Duo @
2.5 GHz. Bigger samples with about 700
2010 Feb 18
2
Extract p-value from aftreg object
Dear all,
does anyone know how I can extract specific p-values for covariates
from an aftreg object? After fitting a model with aftreg I can find
all different variables by using str(), but there's no place where
p-values are kept. The odd thing is that print() displays them
correctly.
EXAMPLE:
> testdata
start stop censor groupvar var1 var2
1 0 1 0
2007 Apr 17
3
Extracting approximate Wald test (Chisq) from coxph(..frailty)
Dear List,
How do I extract the approximate Wald test for the
frailty (in the following example 17.89 value)?
What about the P-values, other Chisq, DF, se(coef) and
se2? How can they be extracted?
######################################################>
kfitm1
Call:
coxph(formula = Surv(time, status) ~ age + sex +
disease + frailty(id,
dist = "gauss"), data = kidney)
2008 Apr 29
2
Help on extract paramters from fitted models
Hi, I have a question about how to extract paramters from a fitted model. I
can extract coefficients and std, but from some other statistics, I dont
know how to extract. Can anyone help?
Here it is an example:
> coxout<-coxph(Surv(t,t.censor)~x)
> coxout
Call:
coxph(formula = Surv(t, t.censor) ~ x)
coef exp(coef) se(coef) z p
x 0.349 1.42 0.257 1.36 0.17
Likelihood
2010 Sep 29
0
eha aftreg overall p-value
Dear useRs,
I am currently fitting an advanced failure time model using G?ran
Brostr?m's excellent "eha" library with the "aftreg" command.
My question: How do I interpret the "Overall p-value", that is
reported at the very bottom of the output? I already figured out it
must be a chi-square test, but I am wondering what a p-value < 0.01
means:
Does it mean
2007 Jul 11
2
p-value from survreg(), library(survival)
dear r experts:
It seems my message got spam filtered, another try:
i would appreciate advice on how to get the p-value from the object 'sr'
created with the function survreg() as given below.
vlad
sr<-survreg(s~groups, dist="gaussian")
Coefficients:
(Intercept) groups
-0.02138485 0.03868351
Scale= 0.01789372
Loglik(model)= 31.1 Loglik(intercept only)= 25.4
2005 Jun 09
2
Weibull survival modeling with covariate
I was wondering if someone familiar
with survival analysis can help me with
the following.
I would like to fit a Weibull curve,
that may be dependent on a covariate,
my dataframe "labdata" that has the
fields "cov", "time", and "censor". Do
I do the following?
wieb<-survreg(Surv(labdata$time,
labadata$censor)~labdata$cov,
2011 Nov 20
1
Cox proportional hazards confidence intervals
I am calculating cox propotional hazards models with the coxph
function from the survival package. My data relates to failure of
various types of endovascular interventions. I can successfully
obtain the LR, Wald, and Score test p-values from the coxph.object, as
well as the hazard ratio as follows:
formula.obj = Surv(days, status) ~ type
coxph.model = coxph(formula.obj, df)
fit =
2020 Jul 15
2
Openblas?
On 2020-07-15 14:36, Dirk Eddelbuettel wrote:
>
> G?ran,
>
> This is not an easy email to reply to because it _contains nothing
> reproducible_.
Thanks Dirk,
Sorry about that, but my real question was (see below): "Is the problem
that openblas uses C versions of blas?" That is, do I need to change
F77_CALL(name)(...);
to
cblas_name(...);
everywhere? And if so, is
2007 Mar 12
2
Lmer Mcmc Summary and p values
Dear R users
I am trying to obtain p-values for (quasi)poisson lmer models, including
Markov-chain Monte Carlo sampling and the command summary.
>
> My problems is that p values derived from both these methods are
totally different. My question is
(1) there a bug in my code and
>
(2) How can I proceed, left with these uncertainties in the estimations of
> the p-values?
>
> Below
2011 Aug 21
3
pooled hazard model with aftreg and time-dependent variables
Dear R-users,
I have two samples with individuals that are in more than one of the samples
and individuals that are only in one sample. I have been trying to do a
pooled hazard model, stacking one sample below the other, with aftreg and
time-dependent covariates. The idea behind is to see aggregate effects of
covariates, but need to control for ther effects of same individuals in both
samples
2008 Jul 16
4
Likelihood ratio test between glm and glmer fits
Dear list,
I am fitting a logistic multi-level regression model and need to test the difference between the ordinary logistic regression from a glm() fit and the mixed effects fit from glmer(), basically I want to do a likelihood ratio test between the two fits.
The data are like this:
My outcome is a (1,0) for health status, I have several (1,0) dummy variables RURAL, SMOKE, DRINK, EMPLOYED,
2010 Mar 14
3
likelihood ratio test between glmer and glm
I am currently running a generalized linear mixed effect model using glmer and I want to estimate how much of the variance is explained by my random factor.
summary(glmer(cbind(female,male)~date+(1|dam),family=binomial,data= liz3"))
Generalized linear mixed model fit by the Laplace approximation
Formula: cbind(female, male) ~ date + (1 | dam)
Data: liz3
AIC BIC logLik deviance
241.3