similar to: "R is not a validated software package..

Let me expand a bit on Thomas's answer. Looking more closely at your data set you have the following: death time group 0 group 1 1.5 0/4 13/13 3 0/4 5/5 8 4/4 0 At time 1.5 group 1 had 13 deaths out of 13 at risk, group 0 had none. Time 8 doesn't have any impact on the fit, since only one group

Dear R-help, I was comparing SAS (I do not know what version it is) and R (version 2.6.0 (2007-10-03) on Linux) survival analyses with time-dependent covariates. The results differed significantly so I tried to understand on a short example where I went wrong. The following example shows that even when argument 'method' in R function coxph and argument 'ties' in SAS procedure

I should hope that there is trouble, since "type III" is an undefined concept for a Cox model. Since SAS Inc fostered the cult of type III they have recently added it as an option for phreg, but I am not able to find any hints in the phreg documentation of what exactly they are doing when you invoke it. If you can unearth this information, then I will be happy to tell you whether

Dear all, I was wondering if anyone can help? I am an R user but recently I have resorted to SAS to calculate the probability of the event (and the associated confidence interval) for the Cox model with combinations of risk factors. For example, suppose I have a Cox model with two binary variables, one for gender and one for treatment, I wish to calculate the probability of survival for the

[cross-posted to -biz and -users since it could fall into either category] Interesting new product that has been introduced that I think some would be interested in here (at least, those users in the United States and perhaps Canada): CNAM delivery via IP lookup. The problem: inbound calls on many PRI connections, and also over many VoIP providers, do not include caller name. This means that

I have a dataset with event=death time (from medical examination until death/censoring) dose (given at examination time) Two groups are considered, a non-exposed group (dose=0), an exposed group (dose between 5 and 60). For some reason there is a theory of the dose increasing its effect over time (however it was only given (and measured) once = at the time of examination). I tested a model:

For time scale that are truly discrete Cox proposed the "exact partial likelihood". I call that the "exact" method and SAS calls it the "discrete" method. What we compute is precisely the same, however they use a clever algorithm which is faster. To make things even more confusing, Prentice introduced an "exact marginal likelihood" which is not

Dear all, I am struggling with calculation of Schoenfeld residuals of my Cox Ph models. Based on the formula as attached, I calculated the Schoenfeld residuals for both non tied and tied data, respectively. And then I validated my results with R using the same data sets. However, I found that my results for non-tied data was ok but the results for tied data were different from R's. How

Hi, I believe ndas devices (http://www.ximeta.com/web/technology/) use raw Ethernet frames, as they require no tcp/ip configuration, the client finds and authenticates with a code that is different for each device sold, like a network mac address. My pc is on a different segment to the ndas devices that we have, the two segments are linked by a linux box that is doing routing and proxy arp, can

Hello Everyone,   I'm learning how to perform various statistical analyses in R. I'm checking my understanding by replicating examples from my SAS books. Below is an attempt to replicate a Cox Proportional Hazards model with a time-varying covariate. I think I'm doing this correctly but am not completely sure. I would appreciate it if someone could double-check my results. In case

Greetings, I am new to R and have been comparing CPH survival analysis hazard ratios between R and SAS PhReg. The binary covariates' HRs are the same, however the continuous variables, for example age, have quite different HRs although in the same direction. SAS PhReg produces HRs which are the change in risk for every one increment change in the independent variable. How do I

Dear all, I want to apply weights to my sample data set and I am struggling with the Efron Approximation with weights. I have got one sample data shown as below: customer week arrest fin age race weight 1 weight 2 weight 3 1 20 1 1 27 1 2 15 2 2 17 1 0 18 1 2 19 1 3 25 1 1 19 0 2 20 1 4 52 0 1 23 1 2 5 1 5 52 0 0 19 0 2 11 1 6 25 1 0 19 0 2 26 1 I applied four different weighted Efron

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If I heard/remember correctly, AT&T's UNIX was proprietary but they released it to academic institutions under NDA and were lax in enforcement. We all know what happened. In this case it's obviously open source, we know what will happen if someone tries something. My main concern is future development, will it remain open source. My real fear is that a certain un-named company is

Dear All, discussing with a statistician of a pharmaceutical company I received this answer about the statistical package that I have planned to use: As R is not a validated software package, we would like to ask if it would rather be possible for you to use SAS, SPSS or another approved statistical software system. Could someone suggest me a 'polite' answer? TIA Giovanni -- dr.

Hi all there Can some one who have experience and knowledge in the pharma industry give me broad details on the subject "Statistical applications for pharma industry". I am new to the subject i.e. what kind of statistical tools used being unique /or atleast specific for pharma industry. It will be of great help as i am actively looking into the subject. though i am quite familiar

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Dear R-Users, A message to continue the discussions we had in March and June. I have read the documents written since then (http://www.r-project.org/doc/R-FDA.pdf ; http://user2007.org/program/presentations/harrell.pdf ; http://user2007.org/program/presentations/rossini.pdf ; http://user2007.org/program/presentations/soukup.pdf) which are very interesting and useful. I work in a CRO and we