Jeremy Miles a écrit : > > At 15:41 10/04/02, Beckman, Anthony wrote: > >Greetings All > > > >I am looking at some code that was given to me for help in learning SPSS. I > >see within it a few lines of syntax that transforms gender values from 1= > >female and 2 = male to -1 = female and 1 = male. > > > >Any specific reasons why someone might do this? Does it help in running > >regressions? > > Yes, using -1 and +1 is a type of coding for using categorical variables in > regression analysis - this is usually referred to as effect coding. Using > this method, the intercept becomes the mean of the DV.

But if the two groups have the same size !

> > Have a look at a book on regression for more info (or do a web search, that > would probably do the trick). > > JM > > Jeremy Miles > mailto:jnvm1@york.ac.uk http://www-users.york.ac.uk/~jnvm1/ > Department of Health Sciences, University of York, Heslington, York, YO10 5DD > *** New phone number: 01904 321375, *** Mobile: 07941 228018

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