I am planning to study survival of preterm babies in a major city in Sri Lanka. To assess the feasibility I need to calculate the sample size as I am going to do it for my thesis. I am planning to follow up them for 1 month(28 days) or 6 months.
Thanks in advance.
Dimuth
try this link http://www-rohan.sdsu.edu/~statctr/calculators/pss5.html. It will be useful to calulate sample size for survival amalysis
Thanks a lot. Would you kindly give me a reference and a formula?. Dimuth
Hello,
To calculate sample sizes I used free online tool as GPower.
Regards, W.
Hi Dimuth,
The source code of the form referenced by Bharathy contains a quite detailed account of the routine used. I just quickly glanced over it, and didn't double-check the references but you might find it interesting. If you're using Google Chrome a direct link to the source code is here: view-source:http://www-rohan.sdsu.edu/~statctr/calculators/pss5.html. In other browsers you can right-/alternative-click on the page and select "View Page Source", "View Source Code" or similar.
Instead of using stand-alone websites or packages for specific purposes, I highly recommend that you choose a statistical software and familiarise yourself with it. R is really neat; it's open source (so you have unrestricted access to the underlying calculations), it's free (so you can work with anybody on your projects, and any reviewer of publications would be able to verify your analyses), and it's used by millions of researchers in essentially all fields. On this page: https://cran.r-project.org/web/views/Survival.html go to the heading "Power Analysis" (about half-way down) where there are some packages that will allow you to do sample size estimations for survival analyses.
There's a bunch of great introductory tutorials and articles for using R, e.g. https://cran.r-project.org/doc/contrib/Torfs+Brauer-Short-R-Intro.pdf.
Hope this is helpful!
Cheers,
Ben
Thanks Ben for your kind reply. I will go through it and will try to use it.
Dimuth
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