Date: Mon, 27 Oct 2008 01:13:02 -0700
Reply-To: "cat.." <cat.b41@GMAIL.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: "cat.." <cat.b41@GMAIL.COM>
Subject: To statisticians: Units, standardization and regression modelling
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Let's say I want to fit a logistic model Logit P(diabetis) = Age +
I usually do not ask for standardizing the covariates before entering
them into the model, only centering them, just to make the
interpretation of exp(beta) easier (= OR when the covariate is
incremented by 1 <unit used in the model>). Centering the covariate
impacts the value of the intercept, reducing them will impact the
value of their coefficient in the model.
But now, I have a doubt: What about the units ? What senses does it
make to add years and mg/dl ?
Any thought about that ?
What is your practice in modeling ? Do you always only work with
standardized variables ?
Thanks to any contributor.