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From | David Crow <david.crow@cide.edu> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: interpretation for negative and positive slope combination of interaction term |
Date | Thu, 9 May 2013 17:34:34 -0500 |
Yes, Nahla and David Hoaglin were absolutely right. Many apologies. David On Thu, May 9, 2013 at 5:06 PM, David Hoaglin <dchoaglin@gmail.com> wrote: > Dear Nahla, > > You are correct about the slope and intercept, as shown in Figure 7.8 > of that book. In David Crow's simplified model, B2 does not > contribute to the slope for MV. > > A major part of your difficulty comes from trying to make ratio > interpretations of coefficients in a model whose coefficients can tell > you about differences. One usual way to get coefficients that have a > straightforward interpretation as ratios is to analyze the dependent > variable in a logarithmic scale. If it is not appropriate to work > with your dependent variable in a log scale, you may be able to use a > generalized linear model with a log link function. > > David Hoaglin > > On Thu, May 9, 2013 at 3:51 PM, Nahla Betelmal <nahlaib@gmail.com> wrote: >> Thanks for the reply David, but I think there is something not quite >> right. If you check this file, p.133 figure 7.8 >> >> http://www.sagepub.com/upm-data/21120_Chapter_7.pdf >> >> You will notice that in order to get the slope for the group with >> Dummy= 1 (overconfident manager in my case), we should add the >> coefficient of beta and gama ( MV and OC*MV in my case) , and to get >> the intercept for those managers we should add the alpha and y ( my >> model intercept and the coefficient of OC ) >> >> I found the same in other files, the problem is that all the examples >> they provide both beta and gama are positive which makes the addition >> and interpretation process easy. >> >> my question is how to add and interpret when one is positive and the >> other is negative . As the effect of MV on realistic managers is - >> 0.0566 and on overconfident managers is + 0.0596 , it moves from >> negative to positive 0.003 (again the interaction is significant >> although at 10 level). how many times MV effect overconfident managers >> more than other managers ? >> >> I would really appreciate help in that >> >> Many thanks >> >> Nahla > * > * 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/ -- Web site for México, las Américas y el Mundo: http://mexicoyelmundo.cide.edu/ ==================================== David Crow Profesor-Investigador/Assistant Professor División de Estudios Internacionales Carretera México-Toluca 3655 Col. Lomas de Santa Fe 01210 México, D.F. Tel.: 5727-9800, ext. 2152 Fax: 5727-9872 ==================================== Conmutador: 5727-98-00 Lada sin costo: 01 800 021 2433 (CIDE) |© * * 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/