Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
| From | graupel75@gmail.com |
| To | Statalist <statalist@hsphsun2.harvard.edu> |
| Subject | st: -stpower- for categorical vars? |
| Date | Fri, 15 Nov 2013 14:57:22 +0800 |
Dear Statalist, I am attempting to calculate the power of some survival analyses, but have more than just a binary variable of interest- that is, I have low, medium and high doses. Let's say I have a study with n=15 for each exposure: stpower cox, n(45) hr // assuming a binary Obviously if I have low-medium-high, the power < 0.6424, but is there any way to calculate that, or should I just use the N from the two smaller categories? stpower cox, n(30) hr There is discussion in the Stata 13 -st- manual about continuous covars of interest (Example 2, pg 281) but not categoricals. Any thoughts? cheers- Andrew Lover ___________________________________________________ Epidemiologist Centre for Infectious Disease Epidemiology Research (CIDER) Saw Swee Hock School of Public Health National University of Singapore * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/