search for: codyh

Dear all, I am trying to find a suitable R-function for parametric proportional hazard regressions. The package survival contains the coxph() function which performs a Cox regression which leaves the base hazard unspecified, i.e. it is a semi-parametric method. The package Design contains the function pphsm() which is good for parametric proportional hazard regressions when the underlying base

Does anyone know of a function that computes the necessary sample size to reject a null median survival in favor of a given alternative median survival in a one arm trial? Cody Hamilton, Ph.D Institute for Health Care Research and Improvement Baylor Health Care System (214) 265-3618 This e-mail, facsimile, or letter and any files or attachments transmitted with it contains information

A few months ago, I posted a query regarding code for a sample size estimate for a one arm survival trial. Below is some code I created to calculate such an estimate - perhaps it may be of some use. #cox.pow computes sample size for a one arm survival trial. med.0 is the null median #survival, med.a is the alternative median survival, a.time is the accrual time, and #f.time is the follow up

I have read some very good reviews comparing R (or Splus) to SAS. Does anyone know if there are any reviews comparing R (or Splus) to Stata? I am trying to get others to try R in my department, and I have never used Stata. Regards, -Cody Cody Hamilton, Ph.D Institute for Health Care Research and Improvement Baylor Health Care System (214) 265-3618 This e-mail, facsimile, or letter

I have a dataset at a hospital level (as opposed to the patient level) that contains number of patients experiencing events (call this number y), and the number of patients eligible for such events (call this number n). I am trying to model logit(y/n) = XBeta. In SAS this can be done in PROC LOGISTIC or GENMOD with a model statement such as: model y/n = <predictors>;. Can this be done

I am trying to use the sas.get function to bring a SAS dataset into R. After calling the sas.get function I got an error message stating that 'sas' is not a recognized internal or external command, etc. I am guessing that I need to specify the internal command to invoke SAS in the sasprog option for the sas.get function, but I don't know how to determine what that command might be.