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From | Steve Samuels <sjsamuels@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st:appropriate test |
Date | Fri, 8 Oct 2010 14:26:00 -0400 |
-- Rajaram Subramanian Potty I recommend that you add all the sampling stages to your design. Include fpcs, especially in the first stage, because you need all the help that you can get in reducing standard errors. something like: svyset psu [pweight=], strata(place) fpc() || _n, strata(round) fpc() One thing is unclear: the sampling frame you used to select males and females. If your sampling frame consisted of households, for example, then replace "_n" in the -svyset- statement above with the household id variable. Which analysis? As you describe your analysis, it is descriptive (or "enumerative"): you want to estimate prevalence rates in one district in 2003 and 200, and their difference. For a descriptive analysis, significance testing is inappropriate. Why? If you had tested every adult in the district, you would never expect the 2002 and 2008 prevalence rates to be _exactly_ the same. (WG Cochran, (1977). Sampling techniques (3rd ed.). New York: Wiley., p.39; WE Deming. (1966). Some theory of sampling. New York: Dover Publications, Chapter 7, p 247, "Distinction between enumerative and analytic studies"). (There are descriptive studies where hypothesis testing is important, e.g. quality assurance sampling ( P Levy and S Lemeshow, Sampling of Populations, Wiley, 2008; p. 429), but your study doesn't seem to be one of them. ) The question is therefore not "Are rates in the two years different?", but "How different are ?" Confidence intervals provide the answer.