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| From | Steven Samuels <sjsamuels@gmail.com> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | Re: st: Using sampling/probability weights for mixed design ANOVA in STATA |
| Date | Tue, 31 May 2011 19:58:28 -0400 |
-- Meg, here's an example of how to do an -anova- analysis with a probability weight. It exploits the fact that -anova- is equivalent to an ordinary multiple regression command (Stata -regress-, for example) and Stata's -regress- _will_ take a probability weight. The trick is to run -regress- without options after -anova- to show the implied predictors that you need to put on the right hand side of the equation. You will need to prefix the categorical factors with "i.". The example is from the -anova- help illustration of a split-plot design: *******START****************** log close log using aovtest, replace text webuse reading anova score prog / class|prog skill prog#skill / class#skill|prog / group|class#skill|prog /, dropemptycells regress // //regression equivalent from -regress- statement after -anova-: add the "i." in front of the categorical variables regress score i.prog i.class#i.prog i.skill i.program#i.skill /// i.class#i.skill#i.program i.group#i.class#i.skill#i.program // regression with probability weight set seed 4816033 gen finalwt =20*(uniform() +.05) // weights>1 regress score i.prog i.class#i.prog i.skill i.program#i.skill /// i.class#i.skill#i.program i.group#i.class#i.skill#i.program, /// pweight(finalwt) // <--pweight option *********END************** Meg, I'm not sure that you should or can do a full-fledged survey analysis,