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From | Chris Ansen <lakridstina@gmail.com> |
To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
Subject | st: Power calculation for ZINB and Poisson Models |
Date | Tue, 30 Apr 2013 09:16:17 +0200 |
Dear all I am trying to do a power calculation with simulated data. Originally I wanted to do one for a zero-inflated negative binomial model, testing three null hypothesis as suggested by Williamson et al. "Power Calculations for ZIP and ZINB Models", Journal of Data Science 2007. It is found easily by typing the title to a Google browser. Here three null-hypotheses are tested: Three null-hypotheses: H0: lamda1 equals 0 nbreg-part of the model H0: beta1 equals 0 logistic part of the model H0: [beta1, lamda1] equals [0,0] joined logistic and nbreg However I started with simulation of the simpler Poisson inspired by: http://www.stata-journal.com/sjpdf.html?articlenum=st0010 and http://www.stata.com/support/faqs/statistics/power-by-simulation/ My problem is that even though I copy the two different approaches and execute them - both gets stuck by the command "generate x =`d1´ in 1 with the error message "in not found" r(111); The commands looks like this: args N r d1 d2 d3 b1 drop _all set obs 3 generate x =`d1´ in 1 and continues exactly as explained in the link The other rather long approach (see link under Poisson with a loop within a loop) - does not work either! I am using STATA SE 11.2 Both examples are copied from the two mentioned links, the only thing I have changed is the `var´, because they copy differently. I have also changed them for this mail not to be bounced from statalist. I have tried the long approach with version 7.0, 11.0 and 11.2 - so this is not the case. I will welcome any advises and solutions - also a more simple approach is very welcome. Thank you for your precious time. Kind regards Christina * * 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/