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From |
"Lachenbruch, Peter" <Peter.Lachenbruch@oregonstate.edu> |

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

Subject |
RE: st: correcting skewness of an indep variables |

Date |
Tue, 16 Mar 2010 09:14:13 -0700 |

Yes, they do. If you have independent variables that have odd distributions, the usual regression treats them as known without error. An error-in-variables model might have some issues. Tony Peter A. Lachenbruch Department of Public Health Oregon State University Corvallis, OR 97330 Phone: 541-737-3832 FAX: 541-737-4001 -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Maarten buis Sent: Tuesday, March 16, 2010 1:25 AM To: stata list Subject: RE: st: correcting skewness of an indep variables --- On Mon, 15/3/10, Lachenbruch, Peter wrote: > If the observations are identifiable a priori (e.g., > hospitalization cost if not hospitalized) you can use a > two-part model. See Lachenbruch, P. A., (2001) > "Comparison of competitors to the two part model" > Statistics in Medicine 20(8) 1215-1234 Lachenbruch, P. A. > (2002) "Analysis of Data with Excess Zeros" Statistical > Methods in Medical Research 11(4) 297-302 > The second reference is an introduction to a volume of SMMR > on this problem. Don't these references deal more with the case where such variables are the depenent/explained/y variable, rather than the case where such variables are the independent/explanatory/x variable? If I understood the original question correctly, than that question concerned the latter case, and the solution I proposed (add the original variable + a dummy indicating which observation had a spike value and which not) is certainly only appropriate for that latter case. -- Maarten -------------------------- Maarten L. Buis Institut fuer Soziologie Universitaet Tuebingen Wilhelmstrasse 36 72074 Tuebingen Germany http://www.maartenbuis.nl -------------------------- * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**RE: st: correcting skewness of an indep variables***From:*"Lachenbruch, Peter" <Peter.Lachenbruch@oregonstate.edu>

**RE: st: correcting skewness of an indep variables***From:*Maarten buis <maartenbuis@yahoo.co.uk>

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