Re: [R] How to perform a Likelihood-ratio test?

2009-07-13 Thread Jeff Xu
Hi Lars, Using the definition of Likelihood-ratio test is straightforward, Jeff Lars Bergemann wrote: Hi. I would like to use a likelihood-ratio test to compare a linear model (lm()) to another linear model containing the first one to see if the extra factors are needed - but I

Re: [R] survival::survfit,plot.survfit

2009-02-26 Thread Jeff Xu
Thanks very much, Bernhard and Terry. It clarify my confusion and really helps a lot. Regards Jeff Xu Terry Therneau wrote: plot(survfit(fit)) should plot the survival-function for x=0 or equivalently beta'=0. This curve is independent of any covariates. This is not correct. It plots

[R] survival::survfit,plot.survfit

2009-02-25 Thread Jeff Xu
I am confused when trying the function survfit. my question is: what does the survival curve given by plot.survfit mean? is it the survival curve with different covariates at different points? or just the baseline survival curve? for example, I run the following code and get the survival curve