search for: s_0

Dear all, I am confused with the output of survfit.coxph. Someone said that the survival given by summary(survfit.coxph) is the baseline survival S_0, but some said that is the survival S=S_0^exp{beta*x}. Which one is correct? By the way, if I use "newdata=" in the survfit, does that mean the survival is estimated by the value of covariates in the new data frame? Thank you very much! Koshihaku -- View this message in context: http...

...me,fustat)~resid.ds+rx+ecog.ps,data=ovarian) plot(survfit(fit,type="breslow")) summary(survfit(fit,type="breslow")) #### for the first two failure points, we have s(59|x1)=0.971, s(115|x2)=0.942 how can we guarantee that s(59|x1) is always greater than s(115|x2)? since s(59|x1)=s_0(59)^exp(\beta'x1) and s(115|x2)=s_0(115)^exp(\beta'x2), we can manipulate covariates to make s(59|x1) < s(115|x2), right? do I miss anything? thanks in advance Jeff -- View this message in context: http://www.nabble.com/survival%3A%3Asurvfit%2Cplot.survfit-tp22206954p22206954.html Se...

Hi, I've attached two files with the sources for a function to implement the finite difference method for solving a particular differential equation. One of them works correctly, the other gives wrong results or returns an error, depending on the version of R. The difference between them is that in the 'broken' version in line 42 I check if the items in the two-dimensional array

Dear Prof. Brostr?m, Dear R-mailinglist, first of all thanks a lot for your great effort to incorporate time-varying covariates into aftreg. It works like a charm so far and I'll update you with detailled benchmarks as soon as I have them. I have one more questions regarding Accelerated Failure Time models (with aftreg): You mention that left truncation in combination with time-varying

...Xt Ht the catch for each period t Xt fishing effort for each period t alpha parameter of boat productivity * the dynamic of the fish stock S(t+1) = S(t) + Gt - Ht I would like to modelise the following system: S_(t+1) = S_t + G_t - H_t G_t = r*S_t*(1-S_t / sbar) H_t = alpha * S_t * X_t S_1961 = S_0 I know only H_t on period (1961 - 1994) and X_t on the same period. I don't know r, sbar, alpha and S_0 (the initial level of the stock) (and of course S_t on this period) and I want to estimate this four parameters. I have written something like that: ***************************************...

Dear R-help, I am trying to obtain the baseline survival estimate of a fitted Cox model (S_0 (t)). I know that previous posts have said use 'basehaz' but this gives the baseline hazard function and not the baseline survival estimate. Is there a way to obtain the baseline survival estimate or do I have to use the formula which does something like S(t) = exp[- the integral from 0 to...

...me,fustat)~resid.ds+rx+ecog.ps,data=ovarian) plot(survfit(fit,type="breslow")) summary(survfit(fit,type="breslow")) #### for the first two failure points, we have s(59|x1)=0.971, s(115|x2)=0.942 how can we guarantee that s(59|x1) is always greater than s(115|x2)? since s(59|x1)=s_0(59)^exp(\beta'x1) and s(115|x2)=s_0(115)^exp(\beta'x2), we can manipulate covariates to make s(59|x1) < s(115|x2), right? do I miss anything? thanks in advance

Dear all, Is there a way to calculate the non-cumulative hazard (instantaneous hazard), which is the product of baseline hazard and exp{beta*covariate} ? I knew in survfit, we can get the estimator of cumulative baseline hazard, but how can we get the non-cumulative one? Thank you very much! Koshihaku -- View this message in context:

...t; that my x axis is in days and i have a starting population of say 10,000 > of which say only 2000 are left as of day 365. When I try to print rmean > it does not print and in any case I am not interested in that. I actually > want to sum up all the daily survival values starting at 1.0 (S_0) for day > 1 through 0.2 (S_365) through day 365. I then want to assume "r% retained > each day" and compute the remaining integral as sum of a geometric series > through infinity ( (S_365 * r) * 1/(1-r) ) or through a specific future > time period (730 for example in which ca...