On Fri, Aug 10, 2012 at 7:36 AM, ONKELINX, Thierry <thierry.onkel...@inbo.be> wrote: > Dear Johan, > > Why should it be complicated? You have a very simple model, thus a very > simple formula. Isn't that great? > > Your formula matches the model. Though Trust~Culture + Structure * > Speed_of_Integration is another option. The model fit is the same, the only > difference is the parameterization of the model.
Note quite, I don't think: A*B is shorthand for A + B + A:B where A:B is the 2nd order (interaction) term. The OP only had the 2nd order term without the main effects. OP: You almost certainly want A*B -- it's strange (though certainly not impossible) to have good models where you only have interactions but not main effects. Cheers, Michael > > Best regards, > > Thierry > > ir. Thierry Onkelinx > Instituut voor natuur- en bosonderzoek / Research Institute for Nature and > Forest > team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance > Kliniekstraat 25 > 1070 Anderlecht > Belgium > + 32 2 525 02 51 > + 32 54 43 61 85 > thierry.onkel...@inbo.be > www.inbo.be > > To call in the statistician after the experiment is done may be no more than > asking him to perform a post-mortem examination: he may be able to say what > the experiment died of. > ~ Sir Ronald Aylmer Fisher > > The plural of anecdote is not data. > ~ Roger Brinner > > The combination of some data and an aching desire for an answer does not > ensure that a reasonable answer can be extracted from a given body of data. > ~ John Tukey > > > -----Oorspronkelijk bericht----- > Van: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > Namens Johan Haasnoot > Verzonden: vrijdag 10 augustus 2012 9:15 > Aan: r-help@r-project.org > Onderwerp: [R] Simple question about formulae in R!? > > Good morning reader, > > > > I have encountered a, probably, simple issue with respect to the *formulae* > of a *regression model* I want to use in my research. I'm researching > alliances as part of my study Business Economics (focus Strategy) at the > Vrije Universiteit in Amsterdam. In the research model I use a moderating > variable, I'm looking for confirmation or help on the formulation of the > model. > > > > The research model consist of 2 explanatory variables, a moderating variable > and 1 response variable. The first explanatory variable is Culture, measured > on a nominal scale and the second is Structure of the alliance, also measured > on a nominal scale. The moderating variable in the relation towards Trust is > Speed of Integration, measured as an interval. > The response variable is Trust, measured on a nominal scale (highly likely a > 5-point Likert scale). Given the research model and the measurement scales, I > intent to use a ordered probit model, often used in Marketing models, to > execute the regression modelling. I can't seem to find confirmation on how to > model the formulae. I have been reading and studying R! for a couple of weeks > now, read a lot of books from the R! series in the past, but I can't get a > grasp on this seemingly simple formulae. I think I understand how to model > multinomial regression (using the R-package MNP), how to execute a Principal > Components Analysis and an Explanatory Factor analysis (obviously I'm using a > questionnaire to collect my data), but the formulae itself seems to be to > simple. > > > > I expect to use the interaction symbol: "Trust~Culture + Structure : > Speed_of_Integration" for the formulae, but is it really this simple? Can > anybody confirm this or help me, advise me on this issue? > > > Kind regards, > > -- > > Met vriendelijke groet, > > Johan Haasnoot > > De Haan & Martojo > Kerklaan 5 > 3645 ES Vinkeveen > Telefoon: 0297-266354 > Mobiel: 06-81827665 > Email: johan.haasn...@dh-m.nl > Website: www.dehaanenmartojo.nl > > [[alternative HTML version deleted]] > > * * * * * * * * * * * * * D I S C L A I M E R * * * * * * * * * * * * * > Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver weer > en binden het INBO onder geen enkel beding, zolang dit bericht niet bevestigd > is door een geldig ondertekend document. > The views expressed in this message and any annex are purely those of the > writer and may not be regarded as stating an official position of INBO, as > long as the message is not confirmed by a duly signed document. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
