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From |
"Antonio Rodrigues Andres" <ara@sam.sdu.dk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
Re: st: weigths |

Date |
Wed, 04 Aug 2004 17:04:12 +0200 |

Asumming the number of deaths follows a Poison distribution. Ln (d/p) is approximately normally distributed with variance 1/E(d) where E(d) is the number of expected deaths >>> ara@sam.sdu.dk 08/04/04 05:01PM >>> no, i dont fit a poisson regression, i use as dep. variable the death rate, >>> C_Daskalakis@mail.jci.tju.edu 08/04/04 04:56PM >>> At 05:20 AM 8/4/2004, Antonio Rodrigues Andres wrote: >The dependent variable is ln(d/p) where d=deaths and p is the >population. The log of the death rate ln(d/p) is normally distributed >with variance 1/E(d), where E(d) is the expected number of deaths. Since >E(d) is proportional to p, the variance of ln(d/p) is inversely >proportional to p, the population size which ranges in my application >from 100,000 to five million. This implies heteroskedasticity. >Observations should be weighted by the square root of the country >population. This is similar to covert OLS into GLS, weighting by the >variance inverse of the residuals. >My question is >regress ln(d/p) x1 x2 [w=pop] is that correct? >how about this alternative way to do it? > >xi: regress ln(d/p) x1 x2 i.country i.year di1-di15 >predict e, residual >gen esq=e^2 >xi: regress esq x1 x2 i.country i.year di1-di15 >predict v >xi: regress ln(d/p) x1 x2 i.country i.year di1-di15 [w=1/v] > >I would appreciate any suggestions or comments Poisson regression? Negative binomial regression? The documents accompanying this transmission may contain confidential health or business information. This information is intended for the use of the individual or entity named above. If you have received this information in error, please notify the sender immediately and arrange for the return or destruction of these documents. ________________________________________________________________ Constantine Daskalakis, ScD Assistant Professor, Biostatistics Section, Thomas Jefferson University, 211 S. 9th St. #602, Philadelphia, PA 19107 Tel: 215-955-5695 Fax: 215-503-3804 Email: c_daskalakis@mail.jci.tju.edu Webpage: http://www.jefferson.edu/medicine/pharmacology/bio/ * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

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